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 maximum memory requested from the system by VxVM
for internal purposes. This tunable has a direct impact on
the performance of VxVM as it prevents one I/O operation
from using all the memory in the system.
VxVM allocates two pools that can grow up to this size, one
for RAID-5 and one for mirrored volumes.
A write request to a RAID-5 volume that is greater than one
tenth of the pool size is broken up and performed in chunks
of one tenth of the pool size.
A write request to a mirrored volume that is greater than
half the pool size is broken up and performed in chunks of
one half of the pool size.
The default value is 134217728 (128MB)
The value of voliomem_maxpool_sz must be at least 10
times greater than the value of vol_maxio.
voliomem_maxpool_sz
The default size of the buffer maintained for error tracing
events. This buffer is allocated at driver load time and is
not adjustable for size while VxVM is running.
The default value is 16384 bytes (16KB).
Increasing this buffer can provide storage for more error
events at the expense of system memory. Decreasing the
size of the buffer can result in an error not being detected
via the tracing device. Applications that depend on error
tracing to perform some responsive action are dependent
on this buffer.
voliot_errbuf_dflt
The default size for the creation of a tracing buffer in the
absence of any other specification of desired kernel buffer
size as part of the trace ioctl.
The default value is 8192 bytes (8KB).
If trace data is often being lost due to this buffer size being
too small, then this value can be tuned to a more generous
amount.
voliot_iobuf_default
537Performance monitoring and tuning
Tuning VxVM