Managing HP Serviceguard A.11.20.20 for Linux, May 2013

• 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 must take the
following precautions to ensure that data is not accidentally overwritten.
◦ The server must 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 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.
In addition, you should observe the following guidelines.
• HP recommends that you avoid a single point of failure by ensuring that the NFS server is
highly available.
NOTE: If network connectivity to the NFS Server is lost, the applications using the imported
file system may hang and it may not be possible to kill them. If the package attempts to halt
at this point, it may not halt successfully.
• Do not use the automounter; otherwise package startup may fail.
• If storage is directly connected to all the cluster nodes and shared, configure it as a local file
system rather than using NFS.
• An NFS file system should not be mounted on more than one mount point at the same time.
• Access to an NFS file system used by a package should be restricted to the nodes that can
run the package.
For more information, see the white paperUsing NFS as a file system type with Serviceguard 11.20
on HP-UX and Linux available at http://www.hp.com/go/linux-serviceguard-docs. This paper
includes instructions for setting up a sample package that uses an NFS-imported file system.
See also the description of fs_name (page 187), fs_type (page 188), and the other file
system-related package parameters.
4.8.3 Planning for Expansion
You can add packages to a running cluster. This process is described in Chapter 7: “Cluster and
Package Maintenance” (page 199).
When adding packages, be sure not to exceed the value of max_configured_packages as
defined in the cluster configuration file (see “Cluster Configuration Parameters ” (page 91)). You
can modify this parameter while the cluster is running if you need to.
4.8.4 Choosing Switching and Failover Behavior
To determine the failover behavior of a failover package (see “Package Types” (page 43)), you
define the policy that governs where Serviceguard will automatically start up a package that is not
running. In addition, you define a failback policy that determines whether a package will be
automatically returned to its primary node when that is possible.
4.8 Package Configuration Planning 107