How to Change the Desired Number of Secondaries for a Device Group

The default number of secondary nodes for a device group is set to one. This setting specifies the number of nodes within a device group that can become primary owner of the group if the primary node fails. The desired number of secondaries value can be set to any integer between one and the number of non-primary provider nodes in the device group.

If the numsecondaries property is changed, secondary nodes are added or removed from the device group if the change causes a mismatch between the actual number of secondaries and the desired number.

This procedure uses scsetup(1M) to set or unset the numsecondaries property for Solstice DiskSuite/Solaris Volume Manager or VxVM disk device groups. Refer to scconf_dg_rawdisk(1M), scconf_dg_sds(1M), scconf_dg_svm(1M), and scconf_dg_vxvm(1M) for information about disk device group options when configuring any device group.

Steps

1. Become superuser on any node of the cluster.

2. Run the scsetup utility.

   # scsetup

   The Main Menu is displayed.

3. To work with disk device groups, type 5 (Device groups and volumes).

   The Device Groups Menu is displayed.

4. To change key properties of a device group, type 6 (Change key properties of a device group).

   The Change Key Properties Menu is displayed.

5. To change the desired number of secondaries, type 2 (Change the numsecondaries property).

   Follow the instructions and type the desired number of secondaries to be configured for the disk device group. After an appropriate value has been entered, the corresponding scconf command is executed, a log is printed, and the user returns to the previous menu.

6. Verify that the disk device group attribute has been changed.

   Look for the device group information that is displayed by the following command.

   # scconf -p

Example 4–13 Changing the Desired Number of Secondaries

The following example shows the scconf command that is generated by scsetup when it configures the desired number of secondaries for a device group (dg-schost-1). This example assumes that the disk group and volume were created previously.

# scconf -c -D name=phys-host-1,nodelist=phys-schost-1:phys-schost-2,phys-schost-3 \
preferenced=true,failback=enabled,numsecondaries=1

# scconf -p | grep Device
Device group name:                             dg-schost-1
   Device group type:                          SDS/SVM
   Device group failback enabled:              yes
   Device group node list:                     phys-schost-1, phys-scost-2, phys-schost-3 
   Device group ordered node list:             yes
   Device group desired number of secondaries: 1
   Device group diskset name:                  dg-schost-1

The following example shows use of a null string value to configure the default number of secondaries. The device group will be configured to use the default value, even if the default value changes.

# scconf -c -D name=diskgrp1, nodelist=host1:host2:host3, \
preferenced=false,failback=enabled,numsecondaries= 
 # scconf -p | grep Device
Device group name:                             dg-schost-1
   Device group type:                          SDS/SVM
   Device group failback enabled:              yes
   Device group node list:                     phys-schost-1, phost-2, phys-schost-3
   Device group ordered node list:             yes
   Device group desired number of secondaries: 1
   Device group diskset name:                  dg-schost-1