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

nfs performance tuning for hp-ux 11.0 and 11i systems page 13

Notes:

Page 13July 22, 2002

local

filesystems

Analyze Filesystem Layout

• The layout of the directory hierarchy and the directory

contents on the NFS server can affect performance

• Directory reading and traversal speeds can be influenced

by the contents of the directories being searched

Ø Number of files in the directory

Ø Number of symbolic links in the directory

Ø Symbolic links pointing to automounted directories

When retrieving the contents of an NFS mounted directory, the client will issue

either a combination of READDIR and LOOKUP calls or a series of READDIRPLUS

requests. The larger the directory, the more calls needed to retrieve the contents.

Symbolic links require still more calls because a READLINK is sent to retrieve the

contents of the link. Symbolic links that point to automount managed directories

are rarely a good idea and should be avoided.

Whenever possible, you should try to “flatten out” the directory hierarchy of your

NFS filesystems to achieve a reasonable balance between the number of

directories and the number of files in those directories. The goal is to minimize the

number of NFS calls required by the client to retrieve the contents of any given

directory, while at the same time to arrange the files in such a way as to reduce the

number of directories needing to be searched by a user for a typical operation.

Some applications have restrictions on where data files can reside. Be sure to

check with your application provider if you have any concerns about supported

directory configurations before re-distributing the files used by an application.