Installation guide

44 Chapter 2:Hardware Installation and Operating System Configuration
Figure 2–4 Single UPS System Configuration
Many vendor-supplied UPS systems include Linux applications that monitor the operational status of
the UPS system through a serial port connection. If the battery power is low, the monitoring software
will initiate a clean system shutdown. As this occurs, the cluster software will be properly stopped,
because it is controlled by a System V run level script (for example, /etc/rc.d/init.d/clus-
ter).
See the UPS documentation supplied by the vendor for detailed installation information.
2.4.4 Configuring Shared Disk Storage
In a cluster, shared disk storage is used to hold service data and two quorum partitions. Because this
storage must be available to both cluster systems, it cannot be located on disks that depend on the
availability of any one system. See the vendor documentation for detailed product and installation
information.
There are some factors to consider when setting up shared disk storage in a cluster:
• External RAID
It is strongly recommended to use use RAID 1 (mirroring) to make service data and the quorum
partitions highly available. Optionally, parity RAID can also be employed for high-availability.
Do not use RAID 0 (striping) alone for quorum partitions because this reduces storage availability.
• Multi-Initiator SCSI configurations