Veritas File System 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

VxFS intent log resizing
The VxFS intent log is allocated when the file system is first created. The size of
the intent log is based on the size of the file system—the larger the file system,
the larger the intent log. The maximum default intent log size for disk layout
Versions 4, 5, and 6 is 16 megabytes. The maximum default intent log size for
disk layout Version 7 is 64 megabytes.
With the Version 6 and 7 disk layouts, you can dynamically increase or decrease
the intent log size using the logsize option of the fsadm command. Increasing
the size of the intent log can improve system performance because it reduces the
number of times the log wraps around. However, increasing the intent log size
can lead to greater times required for a log replay if there is a system failure.
Note: Inappropriate sizing of the intent log can have a negative impact on system
performance.
See the mkfs_vxfs(1M) and the fsadm_vxfs(1M) manual pages.
Extended mount options
The VxFS file system provides the following enhancements to the mount command:
■ Enhanced data integrity modes
■ Enhanced performance mode
■ Temporary file system mode
■ Improved synchronous writes
■ Support for large file sizes
See “Mounting a VxFS file system” on page 28.
See the mount_vxfs(1M) manual page.
Enhanced data integrity modes
For most UNIX file systems, including VxFS, the default mode for writing to a file
is delayed, or buffered, meaning that the data to be written is copied to the file
system cache and later flushed to disk.
A delayed write provides much better performance than synchronously writing
the data to disk. However, in the event of a system failure, data written shortly
before the failure may be lost since it was not flushed to disk. In addition, if space
was allocated to the file as part of the write request, and the corresponding data
17Introducing Veritas File System
Veritas File System features