Managing Serviceguard 14th Edition, June 2007

Understanding Serviceguard Hardware Configurations
Redundant Disk Storage
Chapter 244
set up to trigger a package failover or to report disk failure events to a
Serviceguard, to another application, or by email. For more information,
refer to the manual Using High Availability Monitors (B5736-90046),
available at http://docs.hp.com -> High Availability.
Replacement of Failed Disk Mechanisms
Mirroring provides data protection, but after a disk failure, the failed
disk must be replaced. With conventional disks, this is done by bringing
down the cluster and replacing the mechanism. With disk arrays and
with special HA disk enclosures, it is possible to replace a disk while the
cluster stays up and the application remains online. The process is
described under “Replacing Disks” in the chapter “Troubleshooting Your
Cluster.”
Replacement of Failed I/O Cards
Depending on the system configuration, it is possible to replace failed
disk I/O cards while the system remains online. The process is described
under “Replacing I/O Cards” in the chapter “Troubleshooting Your
Cluster.”
Sample SCSI Disk Configurations
Figure 2-2 shows a two node cluster. Each node has one root disk which
is mirrored and one package for which it is the primary node. Resources
have been allocated to each node so that each node may adopt the
package from the other node. Each package has one disk volume group
assigned to it and the logical volumes in that volume group are mirrored.
Please note that Package A’s disk and the mirror of Package B’s disk are
on one interface while Package B’s disk and the mirror of Package A’s
disk are on a separate bus. This arrangement eliminates single points of
failure and makes either the disk or its mirror available in the event one
of the buses fails.