Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Printers, Software, and Performance
Managing System Performance
Chapter 7 731
NOTE For a JFS file system, you can use mkfs -m to see the parameters the
file system was created with. But adjusting the client’s read/write
buffer size to match is probably not worthwhile because the
configured block size does not govern all of the blocks. See
“Examining File System Characteristics” on page 885.
• On the NFS client, use SAM to check read/write block size.
Go to Networking and Communications/Networked File
Systems/Mounted Remote File Systems, select each imported file
system in turn, pull down the Actions menu and select View More
Information, then View Mount Options.
Read Buffer Size and Write Buffer Size should match the file
system’s block size on the server.
If it does not, you can use SAM to change it.
NOTE Unmount the file system on the NFS client first.
Go back to the Mounted Remote File Systems screen, select the file
system whose read/write buffer sizes you need to change, pull down
the Actions menu and select Modify, then modify the buffer sizes on
the Advanced Options screen.
Checking for Asynchronous Writes
Enabling asynchronous writes tells the NFS server to send the client an
immediate acknowledgment of a write request, before writing the data to
disk. This improves NFS throughput, allowing the client to post a second
write request while the server is still writing out the first.
This involves some risk to data integrity, but in most cases the
performance improvement is worth the risk.
You can use SAM to see whether asynchronous writes are enabled on a
server’s exported file systems.