HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator’s Guide for HP-UX 11.00 and HP-UX 11i November, 2000 HP 9000 Systems Manufacturing Part Number: B3929-90011 E1100 United States © Copyright 1983-2000 Hewlett-Packard Company. All rights reserved..
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Copyright 1979, 1980, 1983, 1985-93 Regents of the University of California. This software is based in part on the Fourth Berkeley Software Distribution under license from the Regents of the University of California. Copyright 1988 Carnegie Mellon University Copyright 1990-1995 Cornell University Copyright 1986 Digital Equipment Corporation. Copyright 1997 Isogon Corporation Copyright 1985, 1986, 1988 Massachusetts Institute of Technology. Copyright 1991-1997 Mentat, Inc.
Contents 1. The VxFS File System Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 JFS 3.3 and OnLineJFS 3.3 Product Availability . . . . . . . . . . . . . . . . . .19 JFS and OnLineJFS Feature Comparison . . . . . . . . . . . . . . . . . . . . . . . .20 Disk Layout Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 Version 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Application-Specific Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Quotas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Access Control Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Support for Large Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Creating a File System with Large Files . . . . . . . . . . . . . . . . . . . . . . .
Contents Fixed Extent Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76 Other Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77 Commands Related to Extent Attributes . . . . . . . . . . . . . . . . . . . . . . . . .79 Failure to Preserve Extent Attributes. . . . . . . . . . . . . . . . . . . . . . . . . .80 4. Online Backup Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Combining mount Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Kernel Tuneables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Internal Inode Table Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Monitoring Free Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Monitoring Fragmentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents quotacheck With VxFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123 Using Quotas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124 A. Kernel Messages Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128 File System Response to Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129 Marking an Inode Bad . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents 10
Preface 11
Introduction The VERITAS© File System System Administrator’s Guide provides information on the most important aspects of administering a VERITAS File System™ (VxFS©).The VERITAS File System is also known as the Journaled File System, or JFS. This guide also provides information on administering the HP OnLineJFS product, an optional add-on product for HP-UX systems. This document describes JFS 3.3 and OnLineJFS 3.3. This guide is for system administrators who configure and maintain HP-UX 11.
Organization • Chapter 1, The VxFS File System,, introduces the features and characteristics of this product. • Chapter 2, Disk Layout, describes and illustrates the major components of VxFS disk layouts. • Chapter 3, Extent Attributes, describes the policies associated with allocation of disk space. • Chapter 4, Online Backup, describes the snapshot backup feature of VxFS. • Chapter 5, Performance and Tuning, describes VxFS tools that optimize system performance.
Related Documents To install JFS 3.3 and OnLineJFS 3.3, and for more information about these products, see the following documents: • For HP-UX 11.00 systems: HP JFS 3.3 and HP OnLineJFS 3.3 Release Notes • For HP-UX 11.10 systems: Release Notes for HP-UX Release 11.10 and HP-UX 11.10 Installation and Configuration Notes • For HP-UX 11i systems: HP-UX 11i Release Notes and HP OnLineJFS 3.3 Release Notes for HP-UX 11i The online manual pages provide additional details on VxFS commands and utilities.
Conventions Typeface monospace Usage Examples computer output, files, Read tuneables from the directories, software elements /etc/vx/tunefstab file. such as command options, See the ls(1) manual page for more function names, and information. parameters monospace (bold) user input # mount -F vxfs /h/filesys italic new terms, book titles, See the User’s Guide for details. emphasis, variables replaced The variable ncsize determines with a name or value the value of...
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The VxFS File System 1 The VxFS File System Chapter 1 17
The VxFS File System Introduction Introduction VxFS is an extent based, intent logging file system. VxFS is particularly geared toward UNIX environments that require high performance and availability and deal with large volumes of data. This chapter provides an overview of major VxFS features that are described in detail in later chapters.
The VxFS File System JFS 3.3 and OnLineJFS 3.3 Product Availability JFS 3.3 and OnLineJFS 3.3 Product Availability HP JFS 3.3 and HP OnLineJFS 3.3 are available for HP-UX 11.00 and later systems. You can download JFS 3.3 for HP-UX 11.00 for free from the HP Software Depot (http://www.software.hp.com), or you can request a free JFS 3.3 CD from the Software Depot. You can purchase HP OnLineJFS 3.3 (product number B3929CA for servers and product number B5118CA for workstations) for HP-UX 11.
The VxFS File System JFS and OnLineJFS Feature Comparison JFS and OnLineJFS Feature Comparison HP-UX supports two separate Journaled File System products: the basic product, JFS, which is built into the HP-UX operating system, and the optional, advanced product, OnLineJFS, which is purchased separately. The following table lists VxFS file system features supported in JFS 3.3 and OnLineJFS 3.3.
The VxFS File System Disk Layout Options Disk Layout Options Three disk layout formats are available with VxFS: Version 2 The Version 2 disk layout supports such features as: • filesets • dynamic inode allocation The Version 2 layout is available with optional support for quotas.
The VxFS File System File System Performance Enhancements File System Performance Enhancements The HFS file system uses block based allocation schemes which provide adequate random access and latency for small files but limit throughput for larger files. As a result, the HFS file system is less than optimal for commercial environments. VxFS addresses this file system performance issue through an alternative allocation scheme and increased user control over allocation, I/O, and caching policies.
The VxFS File System Extent-Based Allocation Extent-Based Allocation Disk space is allocated in 1024-byte sectors to form logical blocks. VxFS supports logical block sizes of 1024, 2048, 4096, and 8192 bytes. The default block size is 1K for file systems up to 8 GB, 2K for file systems up to 16 GB, 4K for file systems up to 32 GB, and 8K for file systems beyond this size. An extent is defined as one or more adjacent blocks of data within the file system.
The VxFS File System Extent-Based Allocation inodes also use an 8K default indirect data extent size but allocate the indirect data extents in clusters to simulate larger extents. Typed Extents NOTE The information in this section applies to the VxFS Version 3 and 4 disk layout. In Version 3 and 4, VxFS introduced a new inode block map organization for indirect extents known as typed extents.
The VxFS File System Extent-Based Allocation for future types. The current typed format is used on regular files only when indirection is needed. Typed records are longer than the previous format and require less direct entries in the inode. Newly created files start out using the old format which allows for ten direct extents in the inode. The inode's block map is converted to the typed format when indirection is needed to offer the advantages of both formats.
The VxFS File System Extent Attributes Extent Attributes VxFS allocates disk space to files in groups of one or more extents. HP OnLineJFS also allows applications to control some aspects of the extent allocation. Extent attributes are the extent allocation policies associated with a file. The setext and getext commands allow the administrator to set or view extent attributes associated with a file, as well as to preallocate space for a file.
The VxFS File System Fast File System Recovery Fast File System Recovery The HFS file system relies on full structural verification by the fsck utility as the only means to recover from a system failure. For large disk configurations, this utility involves a time consuming process of checking the entire structure, verifying that the file system is intact, and correcting any inconsistencies. VxFS provides recovery only seconds after a system failure by utilizing a tracking feature called intent logging.
The VxFS File System Online System Administration Online System Administration With the HP OnLineJFS product, a VxFS file system can be defragmented and resized while it remains online and accessible to users. The following sections contain detailed information about these features. NOTE The online administration features, defragmentation, resizing, and online backup, are available only with the optional HP OnLineJFS product.
The VxFS File System Online System Administration Resizing A file system is assigned a specific size as soon as it is created; the file system may become too small or too large as changes in file system usage take place over time. The HFS file system traditionally offers four solutions to address an inadequate small file system: • Move some users to a different file system. • Move a subdirectory of the file system to a new file system. • Copy the entire file system to a larger file system.
The VxFS File System Online Backup Online Backup The HP OnLineJFS product provides a method of online backup of data using the snapshot feature. An image of a mounted file system instantly becomes an exact read-only copy of the file system at a certain point in time. The original file system is snapped while the copy is called the snapshot. When changes are made to the snapped file system, the old data is first copied to the snapshot.
The VxFS File System Application Interface Application Interface The VxFS file system conforms to the System V Interface Definition (SVID) requirements and supports user access through the Network File System (NFS). Applications that require performance features not available with other file systems can take advantage of VxFS enhancements that are introduced in this section and covered in detail in Chapter 6 , “Application Interface.
The VxFS File System Extended mount Options Extended mount Options The VxFS file system supports extended mount options to specify: • enhanced data integrity modes • enhanced performance modes • temporary file system modes • improved synchronous writes See Chapter 5 , “Performance and Tuning” and mount_vxfs(1M) for details on the VxFS mount options. Enhanced Data Integrity Modes NOTE Performance trade-offs are associated with these mount options.
The VxFS File System Extended mount Options files that are written during the system crash or shutdown can lose data. Any changes to a file are flushed to disk when the file is closed. Enhanced Performance Mode The HFS file system is asynchronous in the sense that structural changes to the file system are not immediately written to disk. File systems are designed this way to provide better performance. However, recent changes to the file system may be lost if a system failure occurs.
The VxFS File System Extended mount Options applications. The default datainlog option to mount greatly improves the performance of small synchronous writes. The convosync=dsync option to mount improves the performance of applications that require synchronous data writes but not synchronous inode time updates. NOTE The use of the convosync=dsync option violates POSIX semantics. NOTE The datainlog and convosync options are available only with the optional HP OnLineJFS product.
The VxFS File System Enhanced I/O Performance Enhanced I/O Performance VxFS provides enhanced I/O performance by applying an aggressive I/O clustering policy. Enhanced I/O Clustering I/O clustering is a technique of grouping multiple I/O operations together for improved performance. The VxFS I/O policies provide more aggressive clustering processes than other file systems and offer higher I/O throughput when using large files; the resulting performance is comparable to that provided by raw disk.
The VxFS File System Enhanced I/O Performance For a discussion of performance benefits, refer to Chapter 5 , “Performance and Tuning”, Chapter 6 , “Application Interface”, vxtunefs(1M), and tunefstab(4).
The VxFS File System Quotas Quotas VxFS supports the Berkeley Software Distribution (BSD) style user quotas, which allocate per-user quotas and limit the use of two principal resources: files and data blocks. The system administrator can assign quotas for each of these resources. Each quota consists of two limits for each resource: • The hard limit represents an absolute limit on data blocks or files. The user may never exceed the hard limit under any circumstances.
The VxFS File System Access Control Lists Access Control Lists An Access Control List (ACL) stores a series of entries that identify specific users or groups and their access privileges for a directory or file. A file may have its own ACL or may share an ACL with other files. ACLs have the advantage of specifying detailed access permissions for multiple users and groups. Refer to getacl (1M) and setacl(1M) for information on viewing and setting ACLs.
The VxFS File System Support for Large Files Support for Large Files VxFS can, theoretically, support files up to two terabytes in size because file system structures are no longer in fixed locations (see Chapter 2 , “Disk Layout”). The maximum size tested and supported on HP-UX 11.x systems is one terabyte. Large files are files larger than two gigabytes in size. NOTE Be careful when enabling large file capability.
The VxFS File System Support for Large Files The mount command defaults to match the current setting of the on-disk flag if specified without the largefiles or nolargefiles option, so it’s best not to specify either option. After a file system is mounted, you can use the fsadm utility to change mount options.
Disk Layout 2 Disk Layout Chapter 2 41
Disk Layout Introduction Introduction Three disk layouts are available with the VxFS file system: Version 2 Version 3 Version 4 NOTE The Version 2 disk layout was designed to support features such as filesets, dynamic inode allocation, and enhanced security. The Version 3 disk layout encompasses all file system structural information in files, rather than at fixed locations on disk, allowing for greater scalability. Version 3 supports files and file systems up to one terabyte in size.
Disk Layout Introduction other disk layouts, it is generally preferable to use the Version 4 layout for new file systems. The vxupgrade command can upgrade an existing Version 3 VxFS file system to the Version 4 layout while the file system remains online. vxupgrade can also upgrade a Version 2 file system to the Version 3 layout. See vxupgrade(1M) for details on upgrading VxFS file systems.You cannot downgrade a file system that has been upgraded.
Disk Layout Disk Space Allocation Disk Space Allocation Disk space is allocated by the system in 1024-byte sectors. An integral number of sectors are grouped together to form a logical block. VxFS supports logical block sizes of 1024, 2048, 4096, and 8192 bytes. The default block size is 1024 bytes for file systems less than 3 gigabytes; 2048 bytes for file systems less than 16 gigabytes; 4096 bytes for file systems less than 32 gigabytes; and 8192 bytes for file systems 32 gigabytes or larger.
Disk Layout The VxFS Version 1 Disk Layout The VxFS Version 1 Disk Layout This section describes the VxFS Version 1 disk layout. NOTE The Version 1 disk layout is not supported on HP-UX. Overview The VxFS Version 1 disk layout, as shown in Figure 2-1, “VxFS Version 1 Disk Layout” includes: • the super-block • the intent log • one or more allocation units These elements are discussed in detail in the sections that follow.
Disk Layout The VxFS Version 1 Disk Layout Super-Block The super-block contains important information about the file system, such as: • the file system type • creation and modification dates • label information • information about the size and layout of the file system • the count of available resources • the file system disk layout version number The super-block is always in a fixed location, offset from the start of the file system by 8192 bytes.
Disk Layout The VxFS Version 1 Disk Layout • an inode modification for the directory size change • an inode modification for the new file • a free inode map update for the allocation of the new file VxFS maintains log records in the intent log for all pending changes to the file system structure and ensures that the log records are written to disk in advance of the changes to the file system.
Disk Layout The VxFS Version 1 Disk Layout Figure 2-2 Allocation Unit Structure Allocation Unit Header Allocation Unit Summary Free Inode Map Extended Inode Operations Map Free Extent Map Inode List Padding Data Blocks One or more allocation units exist per file system. Allocation units are located immediately after the intent log. The number and size of allocation units can be specified when the file system is made. All of the allocation units, except possibly the last one, are of equal size.
Disk Layout The VxFS Version 1 Disk Layout Allocation Unit Summary The allocation unit summary contains the number of inodes with extended operations pending, the number of free inodes, and the number of free extents in the allocation unit. Free Inode Map The free inode map is a bitmap that indicates which inodes are free and which are allocated. A free inode is indicated by the bit being on.
Disk Layout The VxFS Version 1 Disk Layout • time of last access • time of last modification • pointers to the extents that contain the file’s data There are up to ten direct extent address size pairs per inode. Each direct extent address indicates the starting block number of a direct extent; direct extent sizes can vary.
Disk Layout The VxFS Version 2 Disk Layout The VxFS Version 2 Disk Layout This section describes the VxFS Version 2 disk layout. Due to the relatively complex nature of the Version 2 layout, the sections that follow are arranged to cover the following general areas: • Structural elements of the file system that exist in fixed locations. These elements are discussed in “Basic Layout”. • Structural elements of the file system that do not exist in fixed locations.
Disk Layout The VxFS Version 2 Disk Layout Basic Layout This section describes the structural elements of the file system that exist in fixed locations on the disk. The VxFS Version 2 disk layout is illustrated in Figure 2-3, “VxFS Version 2 Disk Layout” and is composed of: • the super-block • the object location table • the intent log • a replica of the object location table • one or more allocation units These and other elements are discussed in detail in the sections that follow.
Disk Layout The VxFS Version 2 Disk Layout Figure 2-3 VxFS Version 2 Disk Layout Super-Block Object Location Table Intent Log Object Location Table Replica Allocation Unit 0 . . .
Disk Layout The VxFS Version 2 Disk Layout The super-block is always in a fixed location, offset from the start of the file system by 8192 bytes. This fixed location enables utilities to easily locate the super-block when necessary. The super-block is 1024 bytes long. Copies of the super-block are kept in allocation unit headers: these copies can be used for recovery purposes if the super-block is corrupted or destroyed (see fsck_vxfs(1M)).
Disk Layout The VxFS Version 2 Disk Layout • a directory block update • an inode modification for the directory size change • an inode modification for the new file • a free inode map update for the allocation of the new file VxFS maintains log records in the intent log for all pending changes to the file system structure, and ensures that the log records are written to disk in advance of the changes to the file system.
Disk Layout The VxFS Version 2 Disk Layout Figure 2-4 Allocation Unit Structure Allocation Unit Header Allocation Unit Summary Free Extent Map Padding Data Blocks One or more allocation units exist per file system. Allocation units are located after the OLT replica. The number and size of allocation units can be specified when the file system is made. All of the allocation units, except possibly the last one, are of equal size.
Disk Layout The VxFS Version 2 Disk Layout one 2048 block extent. The file system uses this bitmapping scheme to find an available extent closest in size to the space required. This keeps files as contiguous as possible for faster performance. Padding It may be desirable to align data blocks to a physical boundary. To facilitate this, the system administrator may specify that a gap be left between the end of the free extent map and the first data block.
Disk Layout The VxFS Version 2 Disk Layout inode allocation unit (IAU) file A file that contains a series of inode allocation units. current usage table (CUT) file A file that contains a series of fileset usage entries. link count table file A file that contains a link count for each inode in the attribute fileset. quotas file A file containing user quota information (for the primary fileset only). Structural files and their components are discussed in the sections that follow.
Disk Layout The VxFS Version 2 Disk Layout one fileset header per fileset (see Figure 2-6, “Fileset Header File”). Each fileset header entry is one block long. The fileset header file is replicated because fileset headers cannot be rebuilt from other data structures. Figure 2-5 Filesets and Structural Files Fileset Inode List File IAU File Inode 0 IAU 0 Inode 1 IAU 1 Inode 2 IAU 2 . . . . . .
Disk Layout The VxFS Version 2 Disk Layout Figure 2-6 Fileset Header File Attribute Fileset Header Entry Primary Fileset Header Entry ...
Disk Layout The VxFS Version 2 Disk Layout • time of last access • time of last modification • pointers to the extents that contain the file’s data There are up to ten direct extent address size pairs per inode. Each direct extent address indicates the starting block number of a direct extent; direct extent sizes can vary. If all of the direct extents are used, two indirect address extents are available for use in each inode.
Disk Layout The VxFS Version 2 Disk Layout VxFS Version 1 file system layout, with the first two inodes reserved and inodes 2 and 3 pre-assigned to the root and lost+found directories. The structural fileset’s inode list is similarly constructed, with certain inodes allocated for specific files and other inodes reserved or unallocated. There are two initial inode list extents for the attribute fileset. These contain the inodes for all structural files needed to find and set up the file system.
Disk Layout The VxFS Version 2 Disk Layout Figure 2-7 Inode Lists Primary Fileset Inode List Attribute Fileset Inode List 0 0 32 1 1 33 34 primary fileset quotas file 2 root 2 3 lost + found 3 CUT 35 LCT 4 4 fileset header 36 fileset header (replica) 5 5 attribute fileset IAU 37 primary fileset IAU 6 6 attribute fileset inode list 38 attribute fileset inode list (replica) 7 7 primary fileset inode list 39 primary fileset inode list (replica) 8 8 40 ... ... ...
Disk Layout The VxFS Version 2 Disk Layout Inode Allocation Unit An Inode Allocation Unit (IAU) contains inode allocation information for a given fileset. Each fileset contains one or more IAUs, each of which details allocation for a set number of inodes. The number of inodes per IAU varies, depending on the block size being used. One IAU exists for every 16,384 inodes in a fileset with the default block size (1024 bytes).
Disk Layout The VxFS Version 2 Disk Layout bit being on. The length of the free inode map is 2K for file systems with 1K or 2K block sizes and is equal to the block size for file systems with larger block sizes. Extended Inode Operations Map The extended inode operations map keeps track of inodes on which operations would remain pending for too long to reside in the intent log. The extended inode operations map is in the same format as the free inode map.
Disk Layout The VxFS Version 2 Disk Layout • The number of blocks currently used by the fileset. • The fileset version number, which is a 64-bit integer that is guaranteed to be at least as large as the largest inode version number. An inode version number is a 64-bit integer that is incremented every time its inode is modified or written to disk and can be used to indicate whether an inode has been modified in any way since the last time it was examined.
Disk Layout The VxFS Version 2 Disk Layout block numbers of the initial inode list extents for the attribute fileset and indicates which inodes within those initial extents reference the fileset header file. Object Location Table Contents The OLT is composed of records for the following: fileset header inodes initial inode list extent addresses current usage table inode This record identifies the inode numbers of the fileset header file and its replica.
Disk Layout The VxFS Version 3 Disk Layout The VxFS Version 3 Disk Layout The Version 3 disk layout allows the file system to scale easily to accommodate large files and large file systems. The Version 1 and 2 disk layouts divided up the file system space into allocation units. The first AU started part way into the file system which caused potential alignment problems depending on where the first AU started. Each allocation unit also had its own summary, bitmaps, and data blocks.
Disk Layout The VxFS Version 3 Disk Layout known, the label file can be used to locate super-block copies if there is structural damage to the file system. device file Records device information such as volume length and volume label, and contains pointers to other structural files. fileset header file Holds information on a per-fileset basis.
Disk Layout The VxFS Version 3 Disk Layout allocated. extent allocation unit summary file Contains the AU summary for each allocation unit, which contains the number of free extents of each size. The summary for an extent is created only when an allocation unit is expanded for use. free extent map file Contains the free extent maps for each of the allocation units. quotas file If the file system supports quotas, there is a quotas file which is used to track the resources allocated to each user.
Disk Layout The VxFS Version 4 Disk Layout The VxFS Version 4 Disk Layout The Version 4 disk layout supports Access Control Lists. The Version 4 disk layout does not include significant physical changes from the Version 3 disk layout. Instead, the policies implemented for Version 4 are different, allowing for performance improvements, file system shrinking, and other enhancements.
Disk Layout The VxFS Version 4 Disk Layout Figure 2-10 VxFS Version 3 Disk Layout Super-block Object Location Table OLT Extent Addresses Initial Inode Extents Fileset Header/ File Inode Number Fileset Header File Inode Initial Inode List Extent Addresses Inode List Inode Inode Allocation .... Unit Inode .... OLT Replica Primary Fileset Header Fileset Header File Inode List inum Structural Fileset Header Fileset Index and Name max_inodes Primary Fileset Header Features .... ....
Extent Attributes 3 Extent Attributes Chapter 3 73
Extent Attributes Introduction Introduction The VxFS file system allocates disk space to files in groups of one or more adjacent blocks called extents. VxFS defines an application interface that allows programs to control various aspects of the extent allocation for a given file (see Chapter 6 , “Application Interface”). The extent allocation policies associated with a file are referred to as extent attributes. The VxFS getext and setext commands allows users to view or manipulate file extent attributes.
Extent Attributes Attribute Specifics Attribute Specifics The two basic extent attributes associated with a file are its reservation and its fixed extent size. The user can preallocate space to the file by manipulating a file’s reservation; the user can also override the default allocation policy of the file system by setting a fixed extent size. Other policies determine the way these attributes are expressed during the allocation process.
Extent Attributes Attribute Specifics Persistent reservation is not released when a file is truncated. The reservation must be cleared or the file must be removed to free reserved space. Fixed Extent Size The VxFS default allocation policy uses a variety of heuristics to determine how to make an allocation to a file when a write requires additional space.
Extent Attributes Attribute Specifics Other Controls The auxiliary controls on extent attributes determine: • whether allocations are aligned • whether allocations are contiguous • whether the file can be written beyond its reservation • whether an unused reservation is released when the file is closed • whether the reservation is a persistent attribute of the file • when the space reserved for a file will actually become part of the file Alignment Specific alignment restrictions coordinate a file’s alloca
Extent Attributes Attribute Specifics Reservation Trimming A reservation request can specify that any unused reservation be released when the file is closed. The file is not completely closed until all processes open against the file have closed it. Reservation Persistence A reservation request can ensure the reservation does not become a persistent attribute of the file. Unused reservation is discarded when the file is closed.
Extent Attributes Commands Related to Extent Attributes Commands Related to Extent Attributes The VxFS commands for manipulating extent attributes are setext and getext; they allow the user to set up files with a given set of extent attributes or view any attributes that are already associated with a file. See getext(1M) and setext(1M) for details on using these commands. NOTE setext functionality is available only with the optional HP OnLineJFS product.
Extent Attributes Commands Related to Extent Attributes • The force keyword issues an error if attributes are lost and the file is not relocated. The ls command has an -e option, which prints the extent attributes of the file. Failure to Preserve Extent Attributes Whenever a file is copied, moved, or archived using commands that preserve extent attributes, there is nevertheless the possibility of losing the attributes.
Online Backup 4 Online Backup Chapter 4 81
Online Backup Introduction Introduction This chapter describes the online backup facility provided with the VxFS file system. The snapshot feature of VxFS can be used to create a snapshot image of a mounted file system, which becomes a duplicate read-only copy of the mounted file system. NOTE Snapshot file systems are available only with the optional HP OnLineJFS product.
Online Backup Snapshot File Systems Snapshot File Systems The VxFS file system provides a mechanism for taking snapshot images of mounted file systems, which is useful for making backups.The snapshot file system is an exact image of the original file system, which is referred to as the snapped file system. The snapshot is a consistent view of the file system “snapped” at the point in time the snapshot is made.
Online Backup Snapshot File Systems Figure 4-1 The Snapshot Disk Structure Super-Block Bitmap Blockmap Data Blocks The super-block is similar to the super-block ofa normal VxFS file system, however, the magic number is different and many of the fields are meaningless. Immediately following the super-block is the bitmap. The bitmap contains one bit for every block on the snapped file system. Initially, all bitmap entries are zero.
Online Backup Snapshot File Systems was made. Initially, the snapshot file system satisfies read requests by simply finding the data on the snapped file system and returning it to the requesting process. When an inode update or a write changes the data in block n of the snapped file system, the old data is first read and copied to the snapshot before the snapped file system is updated.
Online Backup Snapshot File Systems file system.
Online Backup Using a Snapshot File System for Backup Using a Snapshot File System for Backup Once a snapshot file system is created, it can be used to perform a consistent backup of the snapped file system. Backup programs that function using the standard file system tree (such as cpio) can be used without modification on a snapshot file system, since the snapshot presents the same data as the snapped file system.
Online Backup Using a Snapshot File System for Backup device being mounted does not identify the device size in its disk label, or if a size smaller than the entire device is desired. Use the following syntax to create a snapshot file system: mount -F vxfs -o snapof=special|mount_point,snapsize=snapshot_size \ snapshot_special snapshot_mount_point The snapshot file system must be created large enough to hold any blocks on the snapped file system that may be written to while the snapshot file system exists.
Online Backup Using a Snapshot File System for Backup point of /backup/home: • To back up files changed within the last week using cpio: # mount -F vxfs -o snapof=/dev/dsk/c0t0d0, \ snapsize=100000 /dev/dsk/c0t1d0 /backup/home # cd /backup # find home -ctime -7 -depth -print | \ cpio -oc > /dev/rmt/0m # umount /backup/home • To do a full backup of /dev/dsk/c0t0d0 and use dd to control blocking of output onto tape device using vxdump: # vxdump f - /dev/rdsk/c0t0d0 | dd bs=128k > /dev/rmt/0m • To do a level 3
Online Backup Performance of Snapshot File Systems Performance of Snapshot File Systems Snapshot file systems maximize the performance of the snapshot at the expense of writes to the snapped file system. Reads from a snapshot file system will typically perform at nearly the throughput of reads from a normal VxFS file system, allowing backups to proceed at the full speed of the VxFS file system. The performance of reads from the snapped file system should not be affected.
Performance and Tuning 5 Performance and Tuning Chapter 5 91
Performance and Tuning Introduction Introduction For any file system, the ability to provide peak performance is important. Adjusting the available VxFS file system options provides a way to optimize system performance. This chapter describes tools that an administrator can use to optimize VxFS. For information on optimizing an application for use with VxFS, see Chapter 6 , “Application Interface.
Performance and Tuning Choosing a Block Size Choosing a Block Size You specify the block size when a file system is created; it cannot be changed later. The standard HFS file system defaults to a block size of 8K with a 1K fragment size. This means that space is allocated to small files (up to 8K) in 1K increments. Allocations for larger files are done in 8K increments except for the last block, which may be a fragment.
Performance and Tuning Choosing an Intent Log Size Choosing an Intent Log Size The intent log size is chosen when a file system is created and cannot be subsequently changed. The mkfs utility uses a default intent log size of 1024 blocks. The default size is sufficient for most workloads. If the system is used as an NFS server or for intensive synchronous write workloads, performance may be improved using a larger log size.
Performance and Tuning Choosing Mount Options Choosing Mount Options In addition to the standard mount mode (log mode), VxFS provides blkclear, delaylog, tmplog, nolog, and nodatainlog modes of operation. Caching behavior can be altered with the mincache option, and the behavior of O_SYNC and D_SYNC (see fcntl(2)) writes can be altered with the convosync option. The delaylog and tmplog modes are capable of significantly improving performance.
Performance and Tuning Choosing Mount Options tmplog In tmplog mode, intent logging is almost always delayed. This greatly improves performance, but recent changes may disappear if the system crashes. This mode is only recommended for temporary file systems. Fast file system recovery works with this mode. nolog Same as tmplog. nodatainlog The nodatainlog mode should be used on systems with disks that do not support bad block revectoring.
Performance and Tuning Choosing Mount Options mincache The mincache mode has five suboptions: • mincache=closesync • mincache=direct • mincache=dsync • mincache=unbuffered • mincache=tmpcache NOTE The mincache=direct, mincache=dsync, mincache=unbuffered, and mincache=tmpcache modes are only available with the HP OnLineJFS product. The mincache=closesync mode is useful in desktop environments where users are likely to shut off the power on the machine without halting it first.
Performance and Tuning Choosing Mount Options Since the mincache=direct, mincache=unbuffered, and mincache=dsync modes change non-synchronous I/O to synchronous I/O, there can be a substantial degradation in throughput for small to medium size files for most applications. Since the VX_DIRECT and VX_UNBUFFERED advisories do not allow any caching of data, applications that would normally benefit from caching for reads will usually experience less degradation with the mincache=dsync mode.
Performance and Tuning Choosing Mount Options CAUTION Extreme care should be taken when using the convosync=closesync or convosync=delay mode because they actually change synchronous I/O into non-synchronous I/O. This may cause applications that use synchronous I/O for data reliability to fail if the system crashes and synchronously written data is lost. The convosync=direct and convosync=unbuffered mode convert synchronous and data synchronous reads and writes to direct reads and writes.
Performance and Tuning Choosing Mount Options This guarantees that when a file is closed, its data is synchronized to disk and cannot be lost. Thus, once an application is exited and its files are closed, no data will be lost even if the system is immediately turned off.
Performance and Tuning Kernel Tuneables Kernel Tuneables This section describes the kernel tuneables in VxFS. Internal Inode Table Size VxFS caches inodes in an inode table (see Table 5-1, “Inode Table Size”). There is a tuneable in VxFS called vx_ninode that determines the number of entries in the inode table. A VxFS file system obtains the value of vx_ninode from the system configuration file used for making the kernel (/stand/system for example).
Performance and Tuning Monitoring Free Space Monitoring Free Space In general, VxFS works best if the percentage of free space in the file system does not get below 10 percent. This is because file systems with 10 percent or more free space have less fragmentation and better extent allocation. Regular use of the df_vxfs(1M) command to monitor free space is desirable. Full file systems may have an adverse effect on file system performance.
Performance and Tuning Monitoring Free Space length • more than 5 percent of the total file system size available as free extents in lengths of 64 or more blocks A badly fragmented file system will have one or more of the following characteristics: • greater than 5 percent of free space in extents of less than 8 blocks in length • more than 50 percent of free space in extents of less than 64 blocks in length • less than 5 percent of the total file system size available as free extents in lengths of 64 or mo
Performance and Tuning Monitoring Free Space /bin/echo "Reorganizing $i" /bin/timex fsadm -F vxfs -e -E -s $i /bin/timex fsadm -F vxfs -s -d -D $i done > $outfile 2>&1 104 Chapter 5
Performance and Tuning I/O Tuning I/O Tuning NOTE The tuneables and the techniques described in this section are for tuning on a per file system basis and should be used judiciously based on the underlying device properties and characteristics of the applications that use the file system. Performance of a file system can be enhanced by a suitable choice of I/O sizes and proper alignment of the I/O requests based on the requirements of the underlying special device.
Performance and Tuning I/O Tuning The number of parallel read requests of size read_pref_io to have outstanding at one time. The file system uses the product of read_nstream multiplied by read_pref_io to determine its read ahead size. The default value for read_nstream is 1. write_nstream The number of parallel write requests of size write_pref_io to have outstanding at one time. The file system uses the product of write_nstream multiplied by write_pref_io to determine when to do flush behind on writes.
Performance and Tuning I/O Tuning Changes the default initial extent size. VxFS determines, based on the first write to a new file, the size of the first extent to be allocated to the file. Normally the first extent is the smallest power of 2 that is larger than the size of the first write. If that power of 2 is less than 8K, the first extent allocated is 8K. After the initial extent, the file system increases the size of subsequent extents (see max_seqio_extent_size) with each allocation.
Performance and Tuning I/O Tuning Try to align the parameters to match the geometry of the logical disk. With striping or RAID-5, it is common to set read_pref_io to the stripe unit size and read_nstream to the number of columns in the stripe. For striping arrays, use the same values for write_pref_io and write_nstream, but for RAID-5 arrays, set write_pref_io to the full stripe size and write_nstream to 1.
Application Interface 6 Application Interface Chapter 6 109
Application Interface Introduction Introduction The VxFS File System provides enhancements that can be used by applications that require certain performance features. This chapter describes cache advisories and provides information about fixed extent sizes and reservation of space for a file. This chapter describes how the application writer can optimize applications for use with the VxFS. To optimize VxFS for use with applications, see Chapter 5 , “Performance and Tuning.
Application Interface Cache Advisories Cache Advisories The VxFS file system allows an application to set cache advisories for use when accessing files. These advisories are in memory only and they do not persist across reboots. Some advisories are currently maintained on a per-file, not a per-file-descriptor, basis. This means that only one set of advisories can be in effect for all accesses to the file. If two conflicting applications set different advisories, both use the last advisories that were set.
Application Interface Cache Advisories direct I/O request does not allocate storage or extend the file, the inode is not immediately written. The CPU cost of direct I/O is about the same as a raw disk transfer. For sequential I/O to very large files, using direct I/O with large transfer sizes can provide the same speed as buffered I/O with much less CPU overhead. If the file is being extended or storage is being allocated, direct I/O must write the inode change before returning to the application.
Application Interface Cache Advisories write returns to the user. If the file is not extended by the write, the times are updated in memory, and the call returns to the user. If the file is extended by the operation, the inode is written before the write returns. Like direct I/O, the data synchronous I/O feature can provide significant application performance gains.
Application Interface Extent Information Extent Information The VX_SETEXT ioctl allows an application to reserve space for a file, and set fixed extent sizes and file allocation flags. The current state of much of this information can be obtained by applications using the VX_GETEXT ioctl (the getext command provides access to this functionality). For details, see getext(1M), setext(1M), and vxfsio(7). NOTE The VX_SETEXT ioctl is available only with the HP OnLineJFS product.
Application Interface Extent Information VX_GETEXT ioctl. If the VX_TRIM flag is set, when the last close occurs on the inode, the reservation is trimmed to match the file size and the VX_TRIM flag is cleared. Any unused space is freed. This can be useful if an application needs enough space for a file, but it is not known how large the file will become. Enough space can be reserved to hold the largest expected file, and when the file has been written and closed, any extra space will be released.
Application Interface Extent Information reservation amount. This flag can be used to create files with uninitialized data. Because this allows uninitialized data in files, it is restricted to users with appropriate privileges. It is possible to use these flags in combination. For example, using VX_CHGSIZE and VX_NORESERVE changes the file size but does not set any reservation. When the file is truncated, the space is freed.
Application Interface Extent Information the space a file needs, and then set a relatively large fixed extent size. If the file grows beyond the reservation, any new extents are allocated in the fixed extent size. Another use of a fixed extent size occurs with sparse files. The file system usually does I/O in page size multiples. When allocating to a sparse file, the file system allocates pages as the smallest default unit.
Application Interface Get I/O Parameters ioctl Get I/O Parameters ioctl VxFS provides the VX_GET_IOPARAMETERS ioctl to get the recommended I/O sizes to use on a file system. This ioctl can be used by the application to make decisions about the I/O sizes issued to VxFS for a file or file device. For more details on this ioctl, refer to vxfsio(7). For a discussion on various I/O parameters, refer to Chapter 5 , “Performance and Tuning,” and vxtunefs (1M).
Quotas 7 Quotas Chapter 7 119
Quotas Introduction Introduction The VxFS File System supports BSD-style user quotas. The quota system limits the use of two principal resources of a file system: files and data blocks. For each of these resources, users may be assigned quotas.
Quotas Quota Limits Quota Limits Quota limits for individual users can be set up for file and data block usage on a file system. A user quota consists of limits for these resources. The following limits can be set for each resource: • The hard limit is an absolute limit that cannot be exceeded under any circumstances. • The soft limit (which is lower than the hard limit) can be exceeded, but only for a limited time.
Quotas Quotas File on VxFS Quotas File on VxFS A quotas file (named quotas) must exist in the root directory of a file system for any of the quota commands to work. This is a BSD quotas implementation requirement, and is also applicable to VxFS quotas. The quotas file in the root directory is referred to as the external quotas file. VxFS also maintains an internal quotas file for its internal use. The quota administration commands read and write the external quotas file to get or change usage limits.
Quotas Quota Commands Quota Commands NOTE Most of the quotas commands in VxFS (as with HFS) are similar to BSD quotas commands. However, the VxFS quotacheck command is an exception—it is not equivalent to the BSD quotacheck command. In general, quota administration for VxFS is performed using commands similar to HFS quota commands. The VxFS mount command supports a special mount option (-o quota), which can be used to turn on quotas at mount time.
Quotas Using Quotas Using Quotas To use the quota functionality on a file system, quotas need to be turned on. Quotas can be turned on either at mount time or any time after a file system is mounted. NOTE Before turning on quotas, the root directory of the file system must contain a file owned by root, called quotas. Quotas can be turned on for a file system at mount time by giving an option to the mount command: # mount -F vxfs -o quota special /mount_point edquota is a quota editor.
Quotas Using Quotas To turn off quotas for a mounted file system, enter: # umount /mount_point # mount -F vxfs special /mount_point Chapter 7 125
Quotas Using Quotas 126 Chapter 7
Kernel Messages A Kernel Messages Appendix A 127
Kernel Messages Introduction Introduction This appendix contains a listing of diagnostic or error messages generated by the VxFS file system kernel. Each message is accompanied by an explanation and a suggestion on how to handle or correct the underlying problem.
Kernel Messages File System Response to Problems File System Response to Problems When the file system encounters problems, it responds in one of three ways: • marks an inode bad • disables transactions • disables the file system Marking an Inode Bad Inodes can be marked bad if an inode update or a directory-block update fails. In these types of failures, the file system doesn’t know what information is on the disk, and considers all the information that it finds to be invalid.
Kernel Messages File System Response to Problems Although some minor file system operations still work, most simply return EIO. The only thing that can be done when the file system is disabled is to do a umount and run a full fsck. Although a log replay may produce a clean file system, do a full structural check to be safe. To do a full structural check, enter: # fsck -F vxfs -o full -y /dev/rdsk/c1t0d0 The file system usually becomes disabled because of disk errors.
Kernel Messages Kernel Messages Kernel Messages This section lists the VxFS kernel error messages in numerical order. The Explanation sub-section for each message describes the problem, the Action sub-section suggests possible solutions. Each section lists the text of the message. In some cases, several variants of the same message are listed separately.
Kernel Messages Kernel Messages becoming full. If a runaway process has used up all the space, stop that process, find the files created by the process, and remove them. If the file system is out of space, remove files, defragment, or expand the file system. To remove files, use the find command to locate the files that are to be removed. To get the most space with the least amount of work, remove large files or file trees that are no longer needed.
Kernel Messages Kernel Messages the bitmap, the file system has been corrupted. This may have occurred because a user or process wrote directly to the device or used fsdb to change the file system. The VX_FULLFSCK flag is set. If the map that failed was a free extent bitmap, and the VX_FULLFSCK flag can’t be set, then the file system is disabled. • Action Check the console log for I/O errors. If the problem is a disk failure, replace the disk.
Kernel Messages Kernel Messages an immediate directory, the directory entries are stored in the inode, so no block number is reported. If the error is ENOENT or ENOTDIR, an inconsistency was detected in the directory block. This inconsistency could be a bad free count, a corrupted hash chain, or any similar directory structure error. If the error is EIO or ENXIO, an I/O failure occurred while reading or writing the disk block.
Kernel Messages Kernel Messages • Explanation When the kernel tries to read an inode, it checks the inode number against the valid range. If the inode number is out of range, the data structure that referenced the inode number is incorrect and must be fixed. The VX_FULLFSCK flag is set in the super-block so that fsck will do a full structural check the next time it is run. • Action Unmount the file system and use fsck to run a full structural check.
Kernel Messages Kernel Messages Table Size” in Chapter 5 , “Performance and Tuning”). NOTE The tuneable parameter vx_ninode is used to set the value of vxfs_ninode. Message 015 WARNING: msgcnt x: vxfs: mesg mount_point file system can’t WARNING: msgcnt x: vxfs: mesg mount_point file system can’t 015: mark 015: mark vx_ibadinactive inode inumber bad vx_ilisterr inode inumber bad • Explanation An attempt to mark an inode bad on disk, and the super-block update to set the VX_FULLFSCK flag, failed.
Kernel Messages Kernel Messages WARNING: msgcnt x: vxfs: mesg 017: vx_attr_indtrunc mount_point file system inode inumber marked bad WARNING: msgcnt x: vxfs: mesg 017: vx_attr_iremove mount_point file system inode inumber marked bad WARNING: msgcnt x: vxfs: mesg 017: vx_bmap - mount_point file system inode inumber marked bad WARNING: msgcnt x: vxfs: mesg 017: vx_bmap_indirect_ext4 - mount_point file system inode inumber marked bad WARNING: msgcnt x: vxfs: mesg 017: vx_delbuf_flush mount_point file system in
Kernel Messages Kernel Messages WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode WARNING: msgcnt x: vxfs: mesg mount_point file system inode
Kernel Messages Kernel Messages replace the disk. If the problem is not related to an I/O failure, find out how the disk became corrupted. If no user or process is writing to the device, report the problem to your customer support organization. In either case, unmount the file system and use fsck to run a full structural check. Message 019 WARNING: msgcnt x: vxfs: mesg 019: vx_log_add mount_point file system log overflow • Explanation Log ID overflow.
Kernel Messages Kernel Messages sets the VX_FULLFSCK flag and the mount fails. If the error isn’t related to an I/O failure, this may have occurred because a user or process has written directly to the device or used fsdb to change the file system. • Action Check the console log for I/O errors. If the problem is a disk failure, replace the disk. If the problem is not related to an I/O failure, find out how the disk became corrupted.
Kernel Messages Kernel Messages • Explanation There were active files in the file system and they caused the unmount to fail. When the system is halted, the root file system is unmounted. This happens occasionally when a process is hung and it can’t be killed before unmounting the root. • Action fsck will run when the system is rebooted. It should clean up the file system. No other action is necessary.
Kernel Messages Kernel Messages • Explanation Snapshot file system error. When the primary file system is written, copies of the original data must be written to the snapshot file system. If a read error occurs on a primary file system during the copy, any snapshot file system that doesn’t already have a copy of the data is out of date and must be disabled. • Action An error message for the primary file system prints.
Kernel Messages Kernel Messages • Action Make sure the snapshot file system was given the correct amount of space. If it was, determine the activity level on the primary file system. If the primary file system was unusually busy, rerun the backup. If the primary file system is no busier than normal, move the backup to a time when the primary file system is relatively idle or increase the amount of disk space allocated to the snapshot file system. Rerun any backups that failed when the error occurred.
Kernel Messages Kernel Messages Snapshot file system disabled, preceded by a message that specifies the reason. • Action Unmount the snapshot file system, correct the problem specified by the message, and rerun any backups that failed due to the error. Message 033 WARNING: msgcnt x: vxfs: mesg 033: vx_check_badblock mount_point file system had an I/O error, setting VX_FULLFSCK • Explanation When the disk driver encounters an I/O error, it sets a flag in the super-block structure.
Kernel Messages Kernel Messages disabled. • Action Unmount the file system and use fsck to run a full structural check. Report as a bug to your customer support organization. Message 036 WARNING: msgcnt x: vxfs: mesg 036: vx_lctbad mount_point file system link count table lctnumber bad • Explanation Update to the link count table (LCT) failed. For a Version 2 and above disk layout, the LCT contains the link count for all the structural inodes. The VX_FULLFSCK flag is set in the super-block.
Kernel Messages Kernel Messages since fsck is likely to rewrite the sector with the read error. In other cases, you replace or reformat the disk drive and restore the file system from backups. Consult the documentation specific to your system for information on how to recover from disk errors. The disk driver should have printed a message that may provide more information.
Kernel Messages Kernel Messages flag was being set, the file system will probably be disabled and Message 031 will also be printed. If the super-block was being written as a result of a sync operation, no other action is taken. • Action Resolve the condition causing the disk error. If the error was the result of a temporary condition (such as accidentally turning off a disk or a loose cable), correct the condition. Check for loose cables, etc.
Kernel Messages Kernel Messages cannot be written, the file system is disabled. • Action Unmount the file system and use fsck to run a full structural check. Check the console log for I/O errors. If the disk has a hardware failure, it should be repaired before the file system is mounted for write access. Message 042 WARNING: msgcnt x: vxfs: mesg 042: vx_bsdquotaupdate mount_point file system user|group id disk limit reached. • Explanation The hard limit on blocks was reached.
Kernel Messages Kernel Messages Message 045 WARNING: msgcnt x: vxfs: mesg 045: vx_bsdiquotaupdate mount_point file system user|group id inode limit reached. • Explanation The hard limit on inodes was exceeded. Further attempts to create files owned by the user will fail. • Action Remove some files to free inodes.
Kernel Messages Kernel Messages To maintain reliable usage counts, VxFS maintains the user and group quotas files as structural files in the structural fileset. These files are updated as part of the transactions that allocate and free blocks and inodes. For compatibility with the quota administration utilities, VxFS also supports the standard user visible quota files. When quotas are turned off, synced, or new limits are added, VxFS tries to update the external quota files.
Kernel Messages Kernel Messages structural check. Message 057 WARNING: msgcnt x: vxfs: mesg 057: vx_esum_bad mount_point file system extent allocation unit summary number number marked bad • Explanation An I/O error occurred reading or writing an extent allocation unit summary. The VX_FULLFSCK flag is set. If the VX_FULLFSCK flag can’t be set, the file system is disabled. • Action Check the console log for I/O errors. If the problem is a disk failure, replace the disk.
Kernel Messages Kernel Messages An I/O error occurred while writing to the snapshot file system bitmap. There is no problem with the snapped file system, but the snapshot file system is disabled. • Action Check the console log for I/O errors. If the problem is a disk failure, replace the disk. If the problem is not related to an I/O failure, find out how the disk became corrupted. If no user or process was writing to the device, report the problem to your customer support organization.
Kernel Messages Kernel Messages A registered extended attribute intervention routine returned an invalid return code to the VxFS driver during extended attribute inheritance. • Action Determine which vendor supplied the registered extended attribute intervention routine and contact their customer support organization.
Kernel Messages Kernel Messages • Explanation An HSM (Hierarchical Storage Management) agent responded to a DMAPI mount event and returned a message in buffer. • Action Consult the HSM product documentation for the appropriate response to the message. Message 067 WARNING: msgcnt x: vxfs: mesg 067: mount of device_path requires HSM agent • Explanation The file system mount failed because the file system was marked as being under the management of an HSM agent, and no HSM agent was found during the mount.
Kernel Messages Kernel Messages specified by the vxfs:vxfs_ninode and vxfs:vx_bc_bufhwm parameters exceeds available memory; the system may hang under heavy load • Explanation The value of the system tuneable parameters—vx_ninode and vx_bc_bufhwm—add up to a value that is more than 66% of the kernel virtual address space or more than 50% of the physical system memory. VxFS inodes require approximately one kilobyte each, so both values can be treated as if they are in units of one kilobyte.
Kernel Messages Kernel Messages • Action Informational only, no action required.
Glossary access control list (ACL) The information that identifies specific users or groups and their access privileges for a particular file or directory. allocation unit A group of consecutive blocks on a file system that contain resource summaries, free resource maps, and data blocks. Allocation units also contain copies of the super-block.
direct I/O An unbuffered form of I/O that bypasses the kernel’s buffering of data. With direct I/O, the file system transfers data directly between the disk and the user-supplied buffer. See buffered I/O and unbuffered I/O. discovered direct I/O Discovered Direct I/O behavior is similar to direct I/O and has the same alignment constraints, except writes that allocate storage or extend the file size do not require writing the inode changes before returning to the application.
indirect data extent An extent that contains file data and is referenced via an indirect address extent. inode A unique identifier for each file within a file system that contains the data and metadata associated with that file. inode allocation unit A group of consecutive blocks containing inode allocation information for a given fileset. This information is in the form of a resource summary and a free inode map. intent logging A method of recording pending changes to the file system structure.
onto any of the physical addresses available on a system. preallocation A method of allowing an application to guarantee that a specified amount of space is available for a file, even if the file system is otherwise out of space. primary fileset The files that are visible and accessible to the user. quotas Quota limits on system resources for individual users for file and data block usage on a file system. See hard limit and soft limit.
disk. When the write returns to the caller, both the data and the inode have been written to disk. TB Terabyte (240 bytes or 1024 gigabytes). transaction Updates to the file system structure that are grouped together to ensure they are all completed throughput For file systems, this typically refers to the number of I/O operations in a given unit of time. I/O I/O that bypasses the kernel cache to increase I/O performance.
Index A Access control lists, 38 Allocation extent based, 22 Allocation policies, 76 block based, 22 default, 76 extent, 23 extent based, 23 ufs, 28 Allocation unit, 47 Allocation unit header, 48, 56 padding, 50, 57 Allocation unit summary, 49, 56 Allocation units, 45, 52, 55 data blocks, 50, 57 extended inode operations map, 49 free extent map, 49, 56 free inode map, 49 inode list, 50 partial, 48, 56 structure, 47, 55 Application transparency, 31 B Bad block revectoring, 96 blkclear, 32 blkclear mount opt
Index extent allocation unit state, 70 extent allocation unit summary, 70 fileset header, 69 free extent map, 70 inode allocation unit, 69 inode list, 69 label, 69 log, 69 object location table, 68 quotas, 70 sparse, 76, 117 File system buffering, 32 expansion, 103 integrity, 46, 54 structure, 47, 55 File system block size, 80 File system performance x09 enhancements, 22 Files structural, 51, 57 Fileset header, 66 Fileset header file, 57, 69 Filesets, 51, 57 attribute, 57 primary, 57 structural, 57 Fixed e
Index M Maps extended inode operations, 49 extended node operations, 65 free extent, 49, 56 free inode, 49, 64 mincache mount option, 95, 96 mkfs, 40, 44 Modes enhanced data integrity, 32 Monitoring fragmentation, 102 mount, 32 Mount options, 94, 99 blkclear, 95, 96 choosing, 94, 99 combining, 99 convosync, 95, 98 delaylog, 33, 95 extended, 32 largefiles, 39 log, 33, 95 mincache, 95, 96 nodatainlog, 95, 96 nolog, 95, 96 tmplog, 95 Mounting file systems option combinations, 99 with large files, 39 msgcnt fi
Index Temporary directories, 33 Thaw, 117 tmplog mount option, 95 Transactions disabled, 129 Tuneable I/O parameters, 105 Tuning I/O parameters, 105 Typed extents, 24, 35 U Uninitialized storage clearing, 96 Unmount, 130 snapped file system, 88 snapshot file system, 88 Utilities cron, 28 fsadm, 28 fscat, 30 fsck, 47, 55, 65 getext, 79 mkfs, 44 setext, 79 VX_NOEXTEND, 114 VX_NORESERVE, 114 VX_NOREUSE, 113 VX_RANDOM, 113 VX_SEQ, 113 VX_SETCACHE, 111 VX_SETEXT, 114 VX_SNAPREAD, 87 VX_THAW, 117 VX_TRIM, 114 V
