VERITAS File System 3.5 (HP OnlineJFS/JFS 3.5) Administrator's Guide (August 2003)

Appendix C
121
C Disk Layout
Introduction
The disk layout is the way file system information is stored on disk. On VxFS, five different disk layout
versions were created to take advantage of evolving technological developments. The disk layout versions
used on VxFS were:
Some of the disk layout versions were not supported on all UNIX operating systems. Version 2 and 3 file
systems can still be mounted, but this will be disallowed in future releases. Currently, the Version 4 and
Version 5 disk layout can be both created and mounted. Version 5 is the default disk layout version.
The vxupgrade command is provided to upgrade an existing VxFS file system to the Version 4 or Version 5
layout while the file system remains online. You must do an upgrade in steps from older to newer layouts. See
the vxupgrade (1M) manual page for details on upgrading VxFS file systems.
The vxfsconvert command is provided to upgrade Version 2 and 3 disk layouts to the Version 4 disk layout
while the file system is not mounted. Using vxfsconvert, the file system can be converted to the Version 4
layout while offline, then using vxupgrade, you can convert it to Version 5 while online. See the vxfsconvert
(1M) manual page for details on upgrading VxFS disk layouts.
The following additional topics are covered in this appendix: Disk Space Allocation The VxFS Version 4 Disk
Layout:
• Disk Space Allocation
• The VxFS Version 4 Disk Layout
• The VxFS Version 5 Disk Layout
Version 1 The Version 1 disk layout is the original VxFS disk layout provided
with pre-2.0 versions of VxFS.
Version 2 The Version 2 disk layout was designed to support features such as
filesets, dynamic inode allocation, and enhanced security. The
Version 2 layout is available with and without quotas support.
Version 3 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 in size.
Version 4 The Version 4 disk layout encompasses all file system structural
information in files, rather than at fixed locations on disk, allowing
for greater scalability. Version 4 supports files and file systems up
to in size.
Version 5 Version 5 enables the creation of file system sizes up to 4 terabytes.
Files canbe a maximum of twoterabytes. File systems largerthan 2 TB
must be created on a VERITAS Volume Manager volume. Version 5
also enables setting up to 1024 access control list (ACL) entries.