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

nfs performance tuning for hp-ux 11.0 and 11i systems page 84

Notes:

Page 84July 22, 2002

cachefs

Application Binary Caching Solutions

(part 2)

•HP-specific Solution – the rpages Mount Option

Ø Instructs the kernel loader to load entire application

binaries contiguously

Ø Automatic – no further configuration or user

intervention required

Ø Only affects binaries – normal data files are not

read in their entirety, only binaries that are executed

are fully populated

Ø Causes potentially slower initial load time, but

substantially faster subsequent load times

The rpages option instructs CacheFS to behave as follows: whenever an

application residing in a cached NFS filesystem is executed, the kernel checks the

front filesystem to see if a complete copy of the application binary is present in the

local cache; if not, the client will sequentially read the entire application binary

from the server and cache a local copy. This automatic caching of complete

binaries occurs without any user intervention. Any future requests for this file are

satisfied from the front filesystem, and this cached binary will remain intact during

a CacheFS filesystem unmount or a client reboot.

An important point to understand about the rpages functionality is that it only forces

the client to cache complete copies of application files that are executed. It does

not automatically load entire copies of files that the client merely reads.

The rpages option may cause initial binary load times to increase (I.e. the first time

the application is run on a CacheFS client with an un-populated cache) since the

entire binary will be loaded across the network. However, subsequent run times

are usually substantially faster.