Managing Serviceguard NFS for Linux, July 2007

Serviceguard NFS for LINUX Introduction
Limitations of the NFS File Lock Migration Feature
Chapter 110
Limitations of the NFS File Lock Migration
Feature
The following describes limitations of the NFS File Lock Migration
feature:
• Multiple NFS packages are not supported on the same node
The file lock migration feature will not work for multiple NFS
packages running on the same node. So, if file lock migration feature
is enabled then any node configured for NFS package in a cluster,
cannot be configured to run multiple NFS packages. This limitation
is because statd/sm-notify on Linux does not deal with
multi-homed hosts. It does not support multiple IP addresses in
sending server reboot notification.
• Multiple Package IPs are not supported with NFS
A Serviceguard package can support multiple relocatable IP
addresses associated with it. But, if lock migration feature is enabled
then only one IP should be specified for NFS in the package control
script as the NFS server reboot/failover notification can be sent using
only one relocatable IP.
• NFS Defect
The NFS File Lock Migration feature is only supported in SLES10,
SLES9 SP1, and RedHat 4 Update 4. This is due to a defect in NFS,
the file lock migration feature does not work on base SLES9, RH4
U1, RH4 U2 and RH4 U3.
• Do not use NFS Server as an NFS Client
During package halt, SIGKILL signal is sent to the lockd kernel
thread to release file locks so that the filesystem can be unmounted
successfully. If the server is also an NFS client, it loses the NFS file
locks obtained by client-side processes when SIGKILL signal is sent
to the lockd kernel thread with an intention to release server side
locks. So, if the client applications use NFS file locking, it is
suggested not to use the clustered nodes configured for the NFS
package as an NFS client for any server.
• SERVICE_FAIL_FAST_ENABLED should be set to “YES”