Veritas File System 5.0 Administrator's Guide (September 2006)

DescriptionFile
Holds information on a per-fileset basis. This may include the inode
of the fileset's inode list file, the maximum number of inodes allowed,
an indication of whether the file system supports large files, and the
inode number of the quotas file if the fileset supports quotas. When
a file system is created, there are two filesets—the structural fileset
defines the file system structure, the primary fileset contains user
data.
fileset header file
Both the primary fileset and the structural fileset have their own set
of inodes stored in an inode list file. Only the inodes in the primary
fileset are visible to users. When the number of inodes is increased,
the kernel increases the size of the inode list file.
inode list file
Holds the free inode map, extended operations map, and a summary
of inode resources.
inode allocation
unit file
Maps the block used by the file system intent log.log file
Indicates the allocation state of each AU by defining whether each
AU is free, allocated as a whole (no bitmaps allocated), or expanded,
in which case the bitmaps associated with each AU determine which
extents are allocated.
extent allocation
unit state 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.
extent allocation
unit summary file
Contains the free extent maps for each of the allocation units.free extent map
file
Contains quota information in records. Each record contains resources
allocated either per user or per group.
quotas files
The Version 4 disk layout supports Access Control Lists and Block-Level
Incremental (BLI) Backup. BLI Backup is a backup method that stores and retrieves
only the data blocks changed since the previous backup, not entire files. This
saves times, storage space, and computing resources required to backup large
databases.
Figure C-1 shows how the kernel and utilities build information about the structure
of the file system.
The super-block location is in a known location from which the OLT can be located.
From the OLT, the initial extents of the structural inode list can be located along
with the inode number of the fileset header file. The initial inode list extents
contain the inode for the fileset header file from which the extents associated
with the fileset header file are obtained.
Disk layout
VxFS Version 4 disk layout
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