HP Serviceguard Adding the Package to the Cluster, How Control Scripts Manage VxVM Disk Groups

NOTE: For modular packages, you now need to distribute any external scripts identified by the external_pre_script and external_script parameters.

But if you are accustomed to configuring legacy packages, note that you do not have to create a separate package control script for a modular package, or distribute it manually. (You do still have to do this for legacy packages; see “Configuring a Legacy Package” (page 302).)

Adding the Package to the Cluster

You can add the new package to the cluster while the cluster is running, subject to the value of MAX_CONFIGURED_PACKAGES in the cluster configuration file. See “Adding a Package to a Running Cluster” (page 312).

How Control Scripts Manage VxVM Disk Groups

VxVM disk groups (other than those managed by CVM) are outside the control of the Serviceguard cluster. The package control script uses standard VxVM commands to import and deport these disk groups. (For details on importing and deporting disk groups, refer to the discussion of the import and deport options in the vxdg man page.)

The control script imports disk groups using the vxdg command with the -tfCoptions. The -toption specifies that the disk is imported with the noautoimport flag, which means that the disk will not be automatically re-imported at boot time. Since disk groups included in the package control script are only imported by Serviceguard packages, they should not be auto-imported.

The -foption allows the disk group to be imported even if one or more disks (a mirror, for example) is not currently available. The -Coption clears any existing host ID that might be written on the disk from a prior activation by another node in the cluster. If the disk had been in use on another node which has gone down with a TOC, then its host ID may still be written on the disk, and this needs to be cleared so the new node’s ID can be written to the disk. Note that the disk groups are not imported clearing the host ID if the host ID is set and matches a node that is not in a failed state. This is to prevent accidental importation of a disk group on multiple nodes which could result in data corruption.

CAUTION: Although Serviceguard uses the -Coption within the package control script framework,

this option should not normally be used from the command line. Chapter 8: “Troubleshooting Your Cluster” (page 321), shows some situations where you might need to use -Cfrom the command line.

The following example shows the command with the same options that are used by the control script:

#vxdg -tfC import dg_01

This command takes over ownership of all the disks in disk group dg_01, even though the disk currently has a different host ID written on it. The command writes the current node’s host ID on all disks in disk group dg_01 and sets the noautoimport flag for the disks. This flag prevents a disk group from being automatically re-imported by a node following a reboot. If a node in the cluster fails, the host ID is still written on each disk in the disk group. However, if the node is part of a Serviceguard cluster then on reboot the host ID will be cleared by the owning node from all disks which have the noautoimport flag set, even if the disk group is not under Serviceguard control. This allows all cluster nodes, which have access to the disk group, to be able to import the disks as part of cluster operation.

The control script also uses the vxvol startall command to start up the logical volumes in each disk group that is imported.

260 Configuring Packages and Their Services