HP Tru64 UNIX and TruCluster Server Version 5.1B-5 Patch Summary and Release Notes (March 2009)

Use the netstat command to determine if your network is saturated. For Ethernet
networks, a high number of collisions indicates that the network may be saturated.
The following example shows the output from the netstat -I tu0 command:
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs *Coll*
tu0 1500 <Link xx:xx:xx:xx:xx 840386045 0 254319298 5121 5014223
tu0 1500 network client 840386045 0 254319298 5121 5014223
tu0 1500 DLI none 840386045 0 254319298 5121 5014223
3.2.2.20 Tuning the NFS Server Duplicate Request Cache
The NFS server maintains a list of recently completed non-repeatable requests. This
list is used to reply to client retransmissions of the request in the event that the initial
request transmission's reply was lost or that the server took too long to satisfy the
request.
Problems may occur with the duplicate request cache in some cases, under heavy NFS
server load and over high aggregate network bandwidth involving changes to file
systems (changes caused by the use of the creat, link, unlink, mkdir, rmdir,
truncate, utimes, and write commands). These problems can occur if all the
elements in the duplicate request cache are cycled between an initial client transmission
and subsequent retransmission. If this occurs, the NFS server cannot detect that the
retransmission is in fact a retransmission. This may result in the repetition of a request
and may cause out-of-order writes or truncation and subsequent retruncation of a file.
This patch kit provides a tuning variable, nfs_dupcache_size, to control the size
of the NFS server's duplicate request cache, which is measured in the number of
elements that are allocated at NFS server initialization.
If it is determined that the size of the duplicate cache needs to be modified, you should
change nfs_dupcache_size. The new value for nfs_dupcache_size should be
set to equal two times the value of nfs_dupcache_entries.
You must use the dbx command to modify nfs_dupcache_size. There is no sysconfig
interface to this tuning variable.
3.2.2.21 Performance of hwmgr Commands on Large System Configurations
On large system configurations, certain hwmgr commands may take a long time to run
and can produce voluminous output. For example:
• On a system connected to a large storage area network, the hwmgr -view
devices command can take a long time to begin displaying output, because it
must first select devices from all of the hardware components in the system and
then retrieve, format, and sort the output report.
• On a maximally configured AlphaServer GS1280 system with highly interconnected
storage, the hwmgr -view hierarchy command generates thousands of lines
of output.
72 Tru64 UNIX Patches