HP StorageWorks Clustered File System 3.6.0 Windows Storage Server Edition Administration Guide (403103-005, January 2008)

Chapter 7: Configure the SAN 63
As part of managing shared SAN devices, the SCL also gives each disk a
globally unique device identifier that all servers in the cluster use to
access the device. Although the identifiers (such as psd2 or psd2p6)
appear on certain HP CFS Management Console windows, they are
generally only needed for internal use by HP Clustered File System.
Device Identifiers and GPT Disks
When the SCL assigns device identifiers to the partitions on GPT disks, it
skips the first partition because that partition cannot be used by HP
Clustered File System. Therefore, the first identifier, psdXp1, is assigned
to partition 2, the second identifier, psdXp2, is assigned to partition 3, and
so on.
Device Database and Membership Partitions
The SCL stores the device identifier and physical UID for each imported
disk in a device database. When you installed HP Clustered File System,
you specified a set of SAN partitions to be used for the database and for
other functions related to SAN control. These partitions are called
membership partitions and are automatically imported into the cluster. (For
more information about these partitions, see “Membership Partitions” on
page 236.)
HP Clustered File System creates the device database on one of the
membership partitions and then replicates it to the other partitions. The
database must be present for a cluster to form. To ensure that the
database is always available, the recommended configuration is a three-
way mirror.
You can use the utilities described under “Manage Membership
Partitions” on page 240 to fix any problems with the membership
partitions.
Disks Containing More Than 31 Partitions
In HP Clustered File System 3.6, the maximum number of partitions on a
disk or LUN is limited to 31. Disks or LUNs containing a larger number
of partitions cannot be imported into the cluster. If you upgraded to HP
Clustered File System 3.6 from a release earlier than 3.4, you may
currently have imported disks or LUNs with more than 31 partitions, and