Set a disk of each node to be accessed as the iSCSI device from another node. As well as the shared disk device, register the iSCSI device as a resource, and then register it in the shared class. Connect the iSCSI device with the netmirror group.
The object configuration must satisfy the following conditions.
The number of iSCSI devices for mirroring among servers : 16 or less
The shared class where the netmirror group is created
The number of classes: 2 or less
The number of nodes in the scope: 2-node
The number of disks in the class: 8 or less
Any groups except netmirror type, a single disk, and a spare disk cannot be created
The shared class must be registered to the cluster application as the Gds resource
The number of disks in the netmirror group: 2
The JRM attribute of the netmirror volume: on
See
For how to set a disk of each node to be accessed as the iSCSI device from another node, see "4.6 Disk Setting for Performing Mirroring among Servers [4.3A40 or later] [RHEL6]."
Note
When the cluster application is switched, an additional few seconds are required for one netmirror volume. For this reason, lower number of netmirror volumes is recommended.
When the disk on another node cannot be accessed due to a network error, and when the resynchronization copying is performed after the network is restored, I/O to the volume is suspended for a few seconds for one volume. Lower number of volumes is recommended. The time to suspend I/O is about 4 to 5 seconds though it changes depending on the system.
If both nodes are restarted before the shared class where the netmirror volume is created is registered to the cluster application as the Gds resource, the start lock is set in the netmirror volume to protect the data. At this time, the netmirror volume cannot be started. In this case, register the shared class to the cluster application to start the cluster application.
