HP Serviceguard A.11.20- Managing Serviceguard Twentieth Edition, August 2011

3. The mount point packages should not run unless the disk group packages are running.
If the disk groups and mount points are in separate packages, specify the dependencies on
the disk group packages in the configuration file.
CAUTION: Once you create the modular CVM disk group and CFS mount point packages,
you must administer the cluster with cmcheckconf, cmapplyconf, cmrunpkg, cmmodpkg,
and cmrunpkg commands. If you create the legacy CFS packages, you must administer the
cluster with CFS commands, including cfsdgadm, cfsmntadm, cfsmount, and cfsumount.
You must not use the HP-UX mount or umount command to provide or remove access to a
shared file system in a CFS environment; using these HP-UX commands under these
circumstances is not supported. Use cfsmount and cfsumount instead. If you use the HP-UX
mount and umount commands, serious problems could occur, such as writing to the local
file system instead of the cluster file system. Non-CFS commands could cause conflicts with
subsequent CFS command operations on the file system or the Serviceguard packages, and
will not create an appropriate multi-node package, which means cluster packages will not be
aware of file system changes.
NOTE: The Disk Group (DG) and Mount Point (MP) multi-node packages do not monitor the
health of the disk group and mount point. They check that the application packages that
depend on them have access to the disk groups and mount points. If the dependent application
package loses access and cannot read and write to the disk, it will fail, but that will not cause
the DG or MP multi-node package to fail.
4. You create the CFS package, SG-CFS-pkg, with the cfscluster command. It is a system
multi-node package that regulates the volumes used by CVM 4.1 and later. System multi-node
packages cannot be dependent on any other package.
About the Volume Monitor
Simply monitoring each physical disk in a Serviceguard cluster does not provide adequate
monitoring for volumes managed by Veritas Volume Manager from Symantec (VxVM) or logical
volumes managed by HP-UX Logical Volume Manager (LVM), because a physical volume failure
is not always a critical failure that triggers failover (for example, the failure of a single physical
disk within a mirrored volume is not considered critical). For this reason, it can be very difficult to
determine which physical disks must be monitored to ensure that a storage volume is functioning
properly. The HP Serviceguard Volume Monitor provides a means for simple and effective monitoring
of storage volumes.
IMPORTANT: Check the latest version of the release notes (at the address given in the preface
to this manual) for information about Serviceguard support for the volume monitor.
Using the Volume Monitor
NOTE: For LVM, using this monitor is an alternative to using Event Monitoring Service (EMS)
resource dependencies or System Fault Management/custom defined monitors in Serviceguard
using generic resources. EMS does not currently provide a monitor for VxVM.
• See “Using EMS to Monitor Volume Groups” (page 101).
• See “Using Generic Resources to Monitor Volume Groups” (page 100).
Configure the Volume Monitor as a service in a package that requires access to a VxVM or LVM
storage volume.
The package can be a failover package or multi-node package. For example, you can configure
the monitor as a service in a failover package to monitor a storage volume (or multiple storage
volumes) required by the package application. Alternatively, the monitor could be used in a
128 Planning and Documenting an HA Cluster