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Sun Cluster 2.2 System Administration Guide

Changing the Quorum Device

A quorum device is used only in VxVM configurations. It is not used in Solstice DiskSuite configurations.

The scconf -q command can be used to change the quorum device to either a disk or a controller. This option is useful if the quorum device needs servicing. Refer to the scconf(1M) man page for details.

Note -

If the quorum device is a disk, the scconf -q command must be used whenever the disk address (in the form cxtydzs2) changes, even if the serial number of the disk is preserved. This change in disk address can happen if the SBus slot of the drive controller changes.

Caution - Caution -

Do not use the scconf -q option to modify the quorum device topology while the cluster is running. You cannot add or remove a quorum device between any two cluster nodes. Specifically, between a pair of nodes in the cluster, you cannot add a quorum device when there previously was no quorum device, and you cannot specify "no quorum device" if there currently is a quorum device. However, you can change a quorum device (for example, from a disk to another disk) in a running cluster by using the scconf -q option.

How to Change the Quorum Device

  1. Before servicing the device, you can change the quorum device to a different device by running the scconf -q command on all cluster nodes.

    For example, to change the quorum device in the cluster haclust for nodes phys-hahost1 and phys-hahost2, run the scconf(1M) command as shown below.


    # scconf haclust -q phys-hahost1 phys-hahost2
Select quorum device for nodes 0 (phys-hahost1) and 1 (phys-hahost2).
Type the number corresponding to the desired selection.
For example: 1<CR>

 1) DISK:c2t2d0s2:01943825
 2) DISK:c2t3d0s2:09064321
 3) DISK:c2t4d0s2:02171369
 4) DISK:c2t5d0s2:02149886
 5) DISK:c2t8d0s2:09062992
 6) DISK:c2t9d0s2:02166472
 7) DISK:c3t2d0s2:02183692
 8) DISK:c3t3d0s2:02183488
 9) DISK:c3t4d0s2:02160277
10) DISK:c3t5d0s2:02166396
11) DISK:c3t8d0s2:02164352
12) DISK:c3t9d0s2:02164312
Quorum device: 12

    The -q option probes the list of devices attached to each node and lists the devices that the two nodes share. The quorum device can then be selected from this list.

    To enable probing of devices attached to remote hosts, the local /.rhosts file is modified to enable rsh(1) permissions. The permissions are removed after the command completes.

    Note -

    This behavior occurs only if this command is run from all the nodes at the same time. If you do not want remote root access capability, use the -m option.

  2. You may choose either an SSA controller or a disk from this list as the quorum device.

    If you choose an SSA controller, the list of disks in that controller is displayed.

  3. If you chose an SSA controller in Step 2, you are given the option to select a disk from this SSA as the quorum device.

    If no disk is chosen in this step, the SSA controller chosen in the previous step is retained as the quorum device.

    The -q option also checks for the case where a node might have a reservation on the quorum device, due to some other node not being part of the membership. In this case, the -q option releases the reservation on the old quorum device and reserves the new quorum device.

    Note -

    All the specified nodes must be booted for the scconf -q command to run successfully. If any of the nodes is not booted, the command probes and presents the list of all devices on the local node. Be sure to select a shared device as the quorum device.

If you already know the name of the device to use as the quorum device, use the -m option to specify the new device. 


# scconf clustername -q -m quorum-device hostname1 hostname2

The quorum device can either be an SSA controller's World Wide Name (WWN), or a disk identifier of the form WWN.disk-serial-id for disks in SSAs, or a disk identifier of the form disk-address:disk-serial-id for non-SSA disks. The disk-address is of the form cxtydzs2. You can use the finddevices(1M) command to obtain the serial numbers of SSA or non-SSA disks.

If you have a cluster with more than two nodes where all nodes share a common quorum device, you can use the -q -D options to specify a new common quorum device. 


# scconf clustername -q -D

Since all the hosts in the cluster share a common device, specifying a list of hosts is unnecessary.

This is an interactive option that probes the list of devices attached to each host and then presents the list of shared devices. Select the quorum device from this list.

Note -

All the active hosts defined in the cluster must be booted for the scconf -q -D command to be successful. If any of the hosts are not booted, the command probes and presents the list of all devices on the local host. Be sure to select a shared device as the quorum device.

The -q -D combination also checks for the case where a node of the cluster may have a reservation on the quorum device, due to some other node not being part of the cluster. In this case, the reservation on the old quorum device is released and the new quorum device is reserved.

If this command is run from all the nodes at the same time via the cconsole and crlogin GUI interfaces, then the local /.rhosts file is modified to enable rsh(1) permissions. This enables the probing of devices attached to remote hosts. The permissions are removed after the command completes.

The -m option can be added if remote root access capability is not desired. The -m option configures the quorum device and is given as the last argument to the command for the specified nodes.


# scconf clustername -q -D -m quorum-device

The quorum device is a disk identifier of the form cxtydzs2:disk-serial-ID. Use the finddevices(1M) command to obtain the serial numbers of disks.