Quorum disks on HDS USP and NSC

To host quorum disks on HDS USP and NSC storage systems, you must be aware of the system requirements for establishing quorum disk for these storage systems.

Note: Sun StorEdge systems are not supported to host SAN Volume Controller quorum disks.

The SAN Volume Controller cluster uses a quorum disk to store important cluster configuration data and to break a tie in the event of a SAN failure. The cluster automatically chooses three managed disks (MDisks) as quorum disk candidates. Each disk is assigned an index number: either 0, 1, or 2. Although a cluster can be configured to use up to three quorum disks, only one quorum disk is elected to resolve a tie-break situation. The purpose of the other quorum disks is to provide redundancy if a quorum disk fails before the cluster is partitioned.

Requirements for HDS TagmaStore USP, HP XP10000/12000, and NSC55

To host any of the three quorum disks on these HDS TagmaStore USP, HP XP10000/12000, or NSC55 storage systems, ensure that each of the following conditions have been met:

Firmware version Main 50-09-72 00/00 or later is running. Contact HDS or HP support for details on installing and configuring the correct firmware version.
System Option 562 is enabled. Contact HDS or HP support for details on System Option 562.
All SAN Volume Controller ports are configured in a single HDS or HP host group.

Requirements for HDS TagmaStore USPv, USP-VM, and HP XP20000/24000

To host any of the three quorum disks on these HDS TagmaStore USPv, USP-VM, or HP XP20000/24000 systems, ensure that each of the following requirements have been met:

Firmware version Main 60-04-01-00/02 or later is running. Contact HDS or HP support for details on installing and configuring the correct firmware version.
Host Option 39 is enabled. Contact HDS or HP support for details on Host Option 39.
Note: This must be applied to the HDS or HP host group that is used for SAN Volume Controller.
All SAN Volume Controller ports are configured in a single HDS or HP host group.

After you have verified these requirements for the appropriate storage system, complete the following steps on the SAN Volume Controller command-line interface to set the quorum disks:

Issue the svctask chcontroller command:
```
svctask chcontroller -allowquorum yes controller_id or controller_name
```
where controller_id or controller_name is the controller that corresponds to the relevant HDS or HP storage system.
Repeat step 1 for each controller that is part of the relevant HDS or HP storage system.
Issue the svctask setquroum command:
```
svctask setquroum -quorum [0|1|2] mdisk_id or mdisk_name
```
where mdisk_id or mdisk_name is the relevant MDisk on the HDS or HP system.

Attention: Failure to meet these conditions or to follow these steps can result in data corruption.

The Support for SAN Volume Controller (2145) Web site provides current information about quorum support: