Serviceguard NFS Toolkit A.11.11.04 and A.11.23.03 Administrator's Guide

Overview of Serviceguard NFS
Limitations of Serviceguard NFS
Chapter 1 9
Limitations of Serviceguard NFS
The following limitations apply to Serviceguard NFS:
• Applications lose their file locks when an NFS server package moves
to a new node. Therefore, any application that uses file locking must
reclaim its locks after an NFS server package fails over.
An application that loses its file lock due to an NFS package failover
does not receive any notification. If the server is also an NFS client,
it loses the NFS file locks obtained by client-side processes.
NOTE Beginning with Serviceguard NFS A.11.11.03 and A.11.23.02, you
can address this limitation by enabling the File Lock Migration
feature (see “Overview of the NFS File Lock Migration Feature” on
page 10).
To ensure that the File Lock Migration feature functions properly,
install HP-UX 11i v1 NFS General Release and Performance Patch,
PHNE_26388 (or a superseding patch). For HP-UX 11i v2, the
feature functions properly without a patch.
• If a server is configured to use NFS over TCP and the client is the
same machine as the server, which results in a loopback NFS mount,
the client may hang for about 5 minutes if the package is moved to
another node. The solution is to use NFS over UDP between
NFS-HA-server cross mounts.
• The /etc/rmtab file is not synchronized when an NFS package fails
over to the standby node. This is caused by the design of NFS, which
does not keep track of the state of the rmtab. The man page for
rmtab contains a warning that it is not always totally accurate, so it
is also unreliable in a standard NFS server / NFS client
environment.
NOTE You cannot use Serviceguard NFS for an NFS diskless cluster server.
B5140-90021.book Page 9 Wednesday, November 17, 2004 10:52 AM