Tuning HP Tru64 UNIX V5.1A and V5.1B for Oracle

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smsync:23:wait:/sbin/sysconfig -r vfs
smoothsync_age=4 > /dev/null 2>&1
bufcache and bufpages
If none of the file systems are UFS based, then some memory can be freed up by setting the following
parameters. On systems with less than 2 GB of memory, set vfs:bufcache=1. On systems with
more than 2 GB of memory, set vfs:bufpages=2048 and remove any setting of vfs:bufcache
from /etc/sysconfigtab.
IPC Subsystem
Modify the following tunable parameters in the ipc subsystem section of /etc/sysconfigtab.
ssm_threshold
This tunable parameter controls which type of shared memory implementation is used. The default in
Tru64 UNIX V5.x is to use Segmented Shared Memory (SSM) type shared memory. The only two
reasons to change this parameter are the use of statically allocated granularity hints memory or the
use of an application on the same system that prevents the use of SSM type shared memory (for
example, Sybase); in either case ssm_threshold should be set to 0. Note that not using SSM type
shared memory while not using granularity hints memory (which includes those cases where shared
memory allocations exceed the amount of memory reserved for granularity hints) can have a severe
negative performance impact, especially when many processes attach and detach from large shared
memory segments.
HP recommends leaving the value of ssm_threshold at its default value of 8388608, unless
statically allocated granularity hints memory (rad_gh_regions or gh_chunks) is used; in which
case ssm_threshold should be set to 0.
shm_max
This tunable parameter controls the maximum size for a single shared memory segment. Oracle will
automatically concatenate multiple shared memory regions if the SGA is larger then the value
configured for shm_max. As of Tru65 UNIX V5.1, the size for a single shared memory segment could
be larger than 2 GB. However, other applications using shared memory on the same system may
have problems with shared memory segments larger than 2GB. In order to avoid compatibility issues
HP recommends setting the maximum size for an individual shared memory segment to 2 GB.
The recommended (maximum) value for shm_max is 2 GB minus 8 MB, that is:
2147483648 - 8388608 = 0x7f800000 or 2139095040
If only Oracle is being used on the system, you can increase the size of shm_max to 4 GB minus 16
MB, that is:
0xff000000 or 4278190080
shm_min
This tunable parameter specifies the smallest amount of memory allocated for a shared memory
request. The Oracle 9i (9.0.1) System Administration guide incorrectly states a value of 1024 should
be specified; the correct value is the default value of 1.
The error in the Oracle documentation will be corrected in a future release and the typo corrected (the
tunable parameter that should be changed is shm_mni).
The recommended value for shm_min is the default of 1.