NFS Performance Tuning for HP-UX 11.0 and 11i Systems

nfs performance tuning for hp-ux 11.0 and 11i systems page 87

Notes:

Page 87July 22, 2002

cachefs

Measuring CacheFS Effectiveness

(part 1)

• Use cachefsstat(1M) command

Ø Monitor cache hit rate over time

• Compare wall-clock time with and without CacheFS

Ø The timex(1) command reports on wall-clock times

• Use nfsstat(1M) to monitor NFS READ calls

• Be sure to unmount the CacheFS filesystem between

application runs to nullify any effects from buffer cache

and page cache

There are several methodologies for determining whether CacheFS is having a

positive impact on your NFS environment:

1. Use the cachefsstat(1M) command to monitor the cache hit rate over a

period of time.

2. Try performing the same commands via the CacheFS mountpoint and then

via an NFS mountpoint. Use the timex(1) command to see if any noticeable

wall-clock time differences are seen with CacheFS.

3. Perform the same commands via the CacheFS mountpoint several times, but

be sure to unmount and remount the filesystem between attempts to nullify

any effect from the client’s buffer cache or page cache. As before, timex(1)

can be used to compare times between runs. Also, the nfsstat(1M)

command can be used to monitor how many NFS READ calls are made

during each run. The nfsstat(1M) output should show definitively if CacheFS

is eliminating the need for NFS read calls in subsequent runs.