QuickSpecs

The Tru64 UNIX file system architecture is based on the OSF/1 Virtual File System (VFS), which is based on the Berkeley
4.3 Reno Virtual File System. VFS provides a standard interface for file access regardless of the physical file system in
which the files reside.
Tru64 UNIX supports the file system types described in this section.
Advanced File System (AdvFS)
The Advanced File System is a journaled, self-tuning, local file system that provides higher availability and greater flexibility
than traditional UNIX file systems.
Administrators can resize file domains dynamically to allocate or deallocate storage while the system is running, and to set
quotas for users, groups, and filesets. Quotas can have hard and soft limits, which specify a period of time that a quota can
be exceeded.
Using transaction journaling, AdvFS provides increased file system integrity and recovers file domains in seconds rather
than hours after an unexpected restart. The AdvFS defragment utility reduces the number of file extents in a file domain by
making files contiguous, thus improving the read/write performance as less I/O operations are required to access a file.
AdvFS also supports direct I/O. This feature supplies applications that do their own cache and I/O management – for
instance a database – with the ability to bypass the AdvFS cache and I/O management algorithms and deliver near raw disk
performance while still providing all of the system management benefits of a file system.
The AdvFS /, /usr, and /var filesets are configured during installation. The system has generous configuration capabilities.
Administrators can mount 2
32-1
filesets and file domains.
Users can select Atomic Data Logging of a file, which guarantees user data integrity in the event of a system failure.
A single AdvFS file domain may contain up to 256 physical or logical volumes/LUNs with an AdvFS Utilities license installed.
See the System Configuration and Tuning guide for volumes per domain, file domain, and fileset recommendations.
The maximum physical volume size is 1 TB-512 K.
The maximum number of files in a fileset is 2
31
. (This number is limited by the length of the tag that is used to uniquely
identify a file in a fileset.)
The maximum size of an AdvFS file and fileset is 16 TB - 512 K (2
13
* 2
32
), with an 8 K page size and a 31-bit page
number.
AdvFS supports backups of mounted filesets. These backups are done with the vdump or rvdump utilities, which back up
files and any associated extended attributes (including ACLs) from a single mounted fileset or clone of the fileset to a local
or remote storage device. For more information, see the AdvFS Administration guide. The vrestore and rvrestore commands
restore any associated extended attributes, including ACLs, in the archive data.
AdvFS includes the fixfdmn file system repair utility. This utility performs in-place repair of AdvFS file system metadata. This
is a first generation, offline, in place, AdvFS metadata repair tool. The goal of this tool is to re-enable to mount an
unmountable damaged file system after it has been repaired for mounting and I/O operations.
An AdvFS API exists for applications needing access to AdvFS-specific file attributes.
The disk-structure analysis commands allow the system administrator to examine the low-level structures of files, filesets,
and file domains. The verify and slavage utilities may also be useful if a file system has become unmountable by the system
disk due to hardware or software problems.
The right to use the Advanced File System is granted by the Tru64 UNIX Operating System license.
AdvFS Utilities is a separately licensed layered product that expands the capabilities of AdvFS as follows:
Permits adding more than one volume to a file domain.
QuickSpecs
HP Tru64 UNIX Operating System Version V5.1B
File Systems
DA - 11939 U.S. QuickSpecs — Version 1 — 4/8/2004 Page 8