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

nfs performance tuning for hp-ux 11.0 and 11i systems page 32

Notes:

Page 32July 22, 2002

What are biod daemons?

•Biod daemons are the primary NFS client-side daemon

•Their sole purpose is to try to increase the performance of

remote file access by providing read-ahead and write-

behind semantics on the NFS client

•In most cases, but not all, they can dramatically improve

NFS read and write performance

biod

Difference between 11.0 and 11i

Default number of biods on 11.0 = 4 Default on 11i = 16

Biods are the primary NFS client-side daemon. Although they are implemented as

user-space processes, they spend the majority of their time running in the kernel.

Their sole purpose is to try to increase the performance of remote file access by

providing read-ahead and write-behind semantics on the NFS client. In most cases,

but not all, they can dramatically improve NFS read and write performance.

Determining the appropriate number of biod processes to run on a specific NFS

client, like most every other performance issue, is not easily defined and usually

falls into the category of ‘It depends’. Some clients will perform best with 4 biods

while others work better with 16. Still other clients perform best when no biod

daemons are running.

The default number of biods launched at boot time has changed at 11i. 11.0

systems launch 4 biods by default, while 11i NFS clients launch 16.