Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Planning a Workgroup
Planning to Manage File Systems
Chapter 294
No. If the intent log fills up, there is no perceivable impact on users.
Blocking on I/O might occur, but this occurs in many situations unrelated
to the intent log, and will have no perceivable impact. No errors occur if
the intent log fills up.
How can I know the size of the intent log?
You can use fsdb to view the size of the intent log. This file system
debugger should be used by advanced users only, however, as it can
destroy the file system if not used properly. Refer to fsdb_vxfs (1M) for
relevant information, and for information about the JFS superblock
format.
How do I modify the intent log size?
Use the mkfs -F vxfs command with the following -o option: -o
logsize= n , where n is the number of blocks to allocate for the intent log.
n must be in the range 32 to 2048.
For syntax, see mkfs_vxfs (1M).
JFS and the mount Command
What are the JFS mount options and when are they advantageous to use?
JFS offers mount options to delay or disable transaction logging, and to
control whether user data is written synchronously or delayed. These
settings allow the system administrator to make trade-offs between file
system integrity and performance, guaranteeing the integrity of critical
file systems, while optimizing the performance of non-critical or
temporary file systems.
For syntax, see mount_vxfs (1M).
What logging options are available using JFS?
JFS provides a variety of options to control how transactions are logged
to disk, as listed below. The default, log, provides maximum system
integrity in the event of a system failure. Under most other
circumstances, including mounting a JFS file system with SAM and
doing a cold install, the recommended logging mode is delaylog.
log Full logging (default). File system structural changes
are logged to disk before the system call returns to the
application. If the system crashes, fsck will complete
logged operations that have not completed.