Sun Cluster System Administration Guide for Solaris OS

Administering Global Devices and the Global Namespace Overview

Administration of Sun Cluster disk device groups depends on the volume manager that is installed on the cluster. Solstice DiskSuite/Solaris Volume Manager is “cluster-aware,” so you add, register, and remove disk device groups by using the Solstice DiskSuite/Solaris Volume Manager metaset(1M) command. If you are using VERITAS Volume Manager (VxVM), you create disk groups by using VxVM commands. You register the disk groups as Sun Cluster disk device groups with the scsetup(1M) utility. When removing VxVM disk device groups, you use both the scsetup command and VxVM commands.

Sun Cluster software automatically creates a rawdisk device group for each disk and tape device in the cluster. However, cluster device groups remain in an offline state until you access the groups as global devices. When administering disk device groups, or volume manager disk groups, you need to be on the cluster node that is the primary node for the group.

Normally, you do not need to administer the global device namespace. The global namespace is automatically set up during installation and automatically updated during Solaris operating system reboots. However, if the global namespace needs to be updated, you can run the scgdevs(1M) command from any cluster node. This command causes the global namespace to be updated on all other cluster node members, as well as on nodes that might join the cluster in the future.

Global Device Permissions for Solstice DiskSuite/Solaris Volume Manager

Changes made to global device permissions are not automatically propagated to all the nodes in the cluster for Solstice DiskSuite/Solaris Volume Manager and disk devices. If you want to change permissions on global devices, you must manually change the permissions on all the nodes in the cluster. For example, if you want to change permissions on global device /dev/global/dsk/d3s0 to 644, you must execute

# chmod 644 /dev/global/dsk/d3s0

on all nodes in the cluster.

VxVM does not support the chmod command. To change global device permissions in VxVM, consult the VxVM Administrator's Guide.

Dynamic Reconfiguration With Global Devices

Following are issues the you must consider when completing dynamic reconfiguration (DR) operations on disk and tape devices in a cluster.

Caution – Caution –

If the current primary node fails while you are performing the DR operation on a secondary node, cluster availability is impacted. The primary node will have no place to fail over until a new secondary node is provided.

To perform DR operations on global devices, complete the following steps in the order indicated.

Table 4–1 Task Map: Dynamic Reconfiguration with Disk and Tape Devices


For Instructions 

1. If a DR operation that affects an active device group must be performed on the current primary node, switch the primary and secondary nodes before performing the DR remove operation on the device. 

How to Switch the Primary for a Device Group

2. Perform the DR removal operation on the device being removed. 

Sun Enterprise 10000 DR Configuration Guide and the Sun Enterprise 10000 Dynamic Reconfiguration Reference Manual in the Solaris 8 on Sun Hardware and Solaris 9 on Sun Hardware collections.

SPARC: VERITAS Volume Manager Administration Considerations