Managing HP Serviceguard for Linux, Tenth Edition, September 2012

IMPORTANT: Find out the MBTD value for each affected router and switch from
the vendors' documentation; determine all of the possible paths; find the worst case
sum of the MBTD values on these paths; and use the resulting value to set the
Serviceguard CONFIGURED_IO_TIMEOUT_EXTENSION parameter. For instructions,
see the discussion of this parameter under “Cluster Configuration Parameters ”
(page 103).
Switches and routers that do not support MBTD value must not be used in a
Serviceguard NFS configuration. This might lead to delayed packets that in turn
could lead to data corruption.
• Networking among the Serviceguard nodes must be configured in such a way that
a single failure in the network does not cause a package failure.
• Only NFS client-side locks (local locks) are supported.
Server-side locks are not supported.
• Because exclusive activation is not available for NFS-imported file systems, you
should take the following precautions to ensure that data is not accidentally
overwritten.
◦ The server should be configured so that only the cluster nodes have access to
the file system.
◦ The NFS file system used by a package must not be imported by any other system,
including other nodes in the cluster. The only exception to this restriction is when
you want to use the NFS file system as a backing store for HPVM. In this case,
the NFS file system is configured as a multi-node package and is imported on
more than one node in the cluster.
◦ The nodes should not mount the file system on boot; it should be mounted only
as part of the startup for the package that uses it.
◦ The NFS file system should be used by only one package.
◦ While the package is running, the file system should be used exclusively by the
package.
◦ If the package fails, do not attempt to restart it manually until you have verified
that the file system has been unmounted properly.
Package Configuration Planning 123