HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator's Guide

62 Chapter2
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.
Some of the entries in the structural fileset’s inode list are replicas of one
another. For example, inodes 4 and 36 both reference copies of the fileset
header file. The replicated inodes are used by fsck_vxfs(1M)to
reconstruct the file system in the event of damage to either one of the
replicas. Although the two initial inode list extents belonging to the
attribute fileset are logically contiguous, they are physically separated.
This helps to ensure the integrity of the replicated information and
reduces the chance that localized disk damage might result in complete
loss of the file system.
Note that inodes 6 and 38 in the attribute fileset reference the inode list
file for the attribute fileset. In a newly created file system, this file
contains the two inode extents pictured for the attribute fileset.
Likewise, the attribute fileset inodes 7 and 39 reference the inode list file
for the primary fileset. In a newly created file system, this file contains
the single extent pictured for the primary fileset. All of the unused
inodes in the initial extents of the structural inode list are reserved for
future use.