Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Table 16-1
Kernel tunable parameters for VxVM (continued)
DescriptionParameter
The amount of memory, measured in kilobytes, that is
allocated for caching FastResync and cache object metadata.
The default value is 6144KB (6MB).
The memory allocated for this cache is exclusively dedicated
to it. It is not available for other processes or applications.
Setting the value below 512KB fails if cache objects or
volumes that have been prepared for instant snapshot
operations are present on the system.
If you do not use the FastResync or DRL features that are
implemented using a version 20 DCO volume, the value can
be set to 0. However, if you subsequently decide to enable
these features, you can use the vxtune command to change
the value to a more appropriate one:
# vxtune volpagemod_max_memsz value
where the new value is specified in kilobytes. Using the
vxtune command to adjust the value of
volpagemod_max_memsz does not persist across system
reboots unless you also adjust the value that is configured
in the /stand/system file.
volpagemod_max_memsz
The initial amount of memory that is requested from the
system by VxVM for RAID-5 operations. The maximum size
of this memory pool is limited by the value of
voliomem_maxpool_sz.
The default value is 16384 sectors (16MB).
volraid_minpool_size
The maximum number of transient reconstruct operations
that can be performed in parallel for RAID-5. A transient
reconstruct operation is one that occurs on a non-degraded
RAID-5 volume that has not been predicted. Limiting the
number of these operations that can occur simultaneously
removes the possibility of flooding the system with many
reconstruct operations, and so reduces the risk of causing
memory starvation.
The default value is 1.
Increasing this size improves the initial performance on the
system when a failure first occurs and before a detach of a
failing object is performed, but can lead to memory
starvation.
volraid_rsrtransmax
539Performance monitoring and tuning
Tuning VxVM