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

nfs performance tuning for hp-ux 11.0 and 11i systems page 78

Notes:

Page 78July 22, 2002

cachefs

What is CacheFS? (part 2)

•Designed to be used for stable, read-only data

•Since the cache resides in a local filesystem, the

data can survive an unmount or a reboot

•A single cache directory can be used to

cache data from multiple NFS mount points

•An LRU (least recently used) algorithm is used to

remove data from the cache when the configured

disk space or inode thresholds are reached

CacheFS can supply a performance boost to those systems that spend a great deal

of time accessing stable, read-only data over NFS mounts. Since the cache is

maintained on a local client filesystem and not in memory, in most cases the cache

contents remain even if the CacheFS filesystem is unmounted. In fact, the cache

contents remain in the local filesystem even after a client reboot.

A single cache directory can be used to cache data from multiple NFS mounts.

Once the configured thresholds of the cache have been reached, CacheFS

implements a LRU (least recently used) algorithm for invalidating files from the

cache.

Upon mounting a CacheFS filesystem, the kernel launches a number of “cachefsd”

kernel threads to manage the cache contents. These threads are associated with a

single “cachefsd” process.