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

nfs performance tuning for hp-ux 11.0 and 11i systems page 88

Notes:

Page 88July 22, 2002

cachefs

Measuring CacheFS Effectiveness

(part 2)

• Examine the contents of the cache via “ls -l” before

and after unmounting the CacheFS filesystem

Since the CacheFS cache resides in a local filesystem on the NFS client, the actual

contents of the cache can be viewed like any other directory – via the ls(1)

command. The names of the files in the cache do not match the names of the files

in the back filesystem, so some intuition must be used to determine which file in the

front filesystem is the cached equivalent of a specific file in the back filesystem.

In the above example, the /opt/netscape directory was mounted via CacheFS

to an 11i client without the rpages mount option. The Netscape Communicator®

application was launched on the client via the CacheFS mount point. At this point,

an “ls -l” of the cache directory shows a large file (a cached version of the

netscape binary) is resident in the cache. After unmounting the /opt/netscape

directory, a second “ls -l” shows this same file has been zeroed out – effectively

nullifying any CacheFS benefit. As explained previously, the fact that this file was

invalidated from the cache at unmount time indicates that the HP-UX loader used

more than 32 non-contiguous chunks to load the binary, exceeding the 32-slot map

limit.

The before and after “ls -l” outputs of the cache directory provide definitive proof of

whether CacheFS is really offering any benefit to your NFS applications or not.