HP Tru64 UNIX and TruCluster Server Version 5.1B-5 Patch Summary and Release Notes (March 2009)

The output from these commands is gathered and sorted in memory before the report
begins to be displayed. In a system with hundreds or thousands of attached storage
units, the processing stage can take several minutes and you will not see any output
during that time.
When using the command hwmgr -view devices -cluster, the time can be even
longer and the size of the report can be larger because in most clustered configurations,
mass storage devices are reported by every member and thus appear multiple times
in the generated report. Therefore, you may need to relax the memory limits for the
process running the command, because with such a large number of devices in the
configuration, the system may be unable to gather all of the data with the default
memory limit.
We recommend that you run commands that generate large reports in the background
(for example, in a batch job) and save their output into a file or set of files for subsequent
examination or historical comparison.
3.2.2.22 LSM Spin Lock Issue
A patch in this kit addresses a spin lock issue in the LSM kernel that may occur under
extremely heavy I/O loads on multiprocessor systems.
To reduce the need for certain spin locks in the kernel I/O code, you can set a new
sysconfigtab variable, Max_LSM_IO_PERFORMANCE, to 1 (the default is 0). Doing
this will increase LSM I/O performance if it is found that performance is degraded
because of a highly contentious spin lock.
Note that using this spin lock performance feature reduces some of the debugging
statistics that are normally maintained.
In order to use this feature, you must allow at least one LSM I/O daemon (voliod).
The voliod daemon was changed to prevent the number of LSM kernel I/O daemons
from being set to zero if this spin lock performance feature is turned on.
The change to the following voliod command produces an error and the number of
LSM kernel I/O daemons remain unchanged:
# voliod -f set 0
lsm:voliod: ERROR: VOL_IO_DAEMON_SET failed: Permission denied
3.2.2.23 Possible Problem when Processing Many Command Parameters
When running commands or scripts that must process a large amount of command
parameters, your system may hang or you may see an error similar to this: /sbin/ls:
arg list too long.
If this occurs, try rerunning the command or script after entering the following command
to relax the command-line limits:
# sysconfig -r proc exec_disable_arg_limit=1
This kernel setting should not be used as a default. It should only be enabled when
encountering a problem where the exec() argument size limit has been approached.
3.2 Prior Release Notes 73