Managing HP Serviceguard A.11.20.20 for Linux, May 2013

NOTE: Generic resources influence the package based on their status. The actual monitoring
of the resource should be done in a script and this must be configured as a service. The script
sets the status of the resource based on the availability of the resource. See “Monitoring Script
for Generic Resources” (page 297).
Create a list by package of volume groups, logical volumes, and file systems. Indicate which nodes
need to have access to common file systems at different times.
HP recommends that you use customized logical volume names that are different from the default
logical volume names (lvol1, lvol2, etc.). Choosing logical volume names that represent the
high availability applications that they are associated with (for example, lvoldatabase) will
simplify cluster administration.
To further document your package-related volume groups, logical volumes, and file systems on
each node, you can add commented lines to the /etc/fstab file. The following is an example
for a database application:
# /dev/vg01/lvoldb1 /applic1 ext3 defaults 0 1 # These six entries are
# /dev/vg01/lvoldb2 /applic2 ext3 defaults 0 1 # for information purposes
# /dev/vg01/lvoldb3 raw_tables ignore ignore 0 0 # only. They record the
# /dev/vg01/lvoldb4 /general ext3 defaults 0 2 # logical volumes that
# /dev/vg01/lvoldb5 raw_free ignore ignore 0 0 # exist for Serviceguard's
# /dev/vg01/lvoldb6 raw_free ignore ignore 0 0 # HA package. Do not uncomment.
Create an entry for each logical volume, indicating its use for a file system or for a raw device.
CAUTION: Do not use /etc/fstab to mount file systems that are used by Serviceguard packages.
For information about creating, exporting, and importing volume groups, see “Creating the Logical
Volume Infrastructure ” (page 145).
4.8.2 Planning for NFS-mounted File Systems
As of Serviceguard A.11.20.00, you can use NFS-mounted (imported) file systems as shared
storage in packages.
The same package can mount more than one NFS-imported file system, and can use both cluster-local
shared storage and NFS imports.
NOTE: Ensure that the NFS module is loaded during boot time for the configurations using NFS
file systems as part of the package configuration.
The following rules and restrictions apply.
• NFS mounts are supported for modular failover packages.
• So that Serviceguard can ensure that all I/O from a node on which a package has failed is
flushed before the package restarts on an adoptive node, all the network switches and routers
between the NFS server and client must support a worst-case timeout, after which packets and
frames are dropped. This timeout is known as the Maximum Bridge Transit Delay (MBTD).
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 91).
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.
106 Planning and Documenting an HA Cluster