HP Serviceguard manual Additional Points To Note

IMPORTANT: HP does not recommend such configurations. See “ip_subnet” (page 242).

•You cannot detach packages when the HP-UX Clustered I/O Congestion Control feature is enabled.

•As of the date of this manual, you cannot detach ECMT-based packages.

Additional Points To Note

Keep the following points in mind.

•When packages are detached, they continue to run, but without high availability protection.

Serviceguard does not detect failures of components of detached packages, and packages are not failed over. Serviceguard will not provide local LAN failover of IP addresses if the node has been halted in detach mode.

IMPORTANT: This means that you will need to detect any errors that occur while the package is detached, and take corrective action by running cmhaltpkg to halt the detached package and cmrunpkg (1m) to restart the package on another node.

•cmviewcl (1m) reports the status and state of detached packages as detached.

This is true even if a problem has occurred since the package was detached and some or all of the package components are not healthy or not running.

•Because Serviceguard assumes that a detached package has remained healthy, the package is considered to be UP for dependency purposes.

This means, for example, that if you halt node1, detaching pkgA, and pkgB depends on pkgA to be UP on ANY_NODE, pkgB on node2 will continue to run (or can start) while pkgA is detached. See “About Package Dependencies” (page 137) for more information about dependencies.

•As always, packages cannot start on a halted node or in a halted cluster.

•When you restart a node or cluster whose packages have been detached, the packages are re-attached; that is, Serviceguard begins monitoring them again.

At this point, Serviceguard checks the health of the packages that were detached and takes any necessary corrective action — for example, if a failover package has in fact failed while it was detached, Serviceguard will halt it and restart it on another eligible node.

CAUTION: Serviceguard does not check LVM volume groups and mount points when re-attaching packages.

•The detached state and status could appear to persist across a reboot.

If a node reboots while packages are detached (or detaching, or re-attaching), and package components are left in an inconsistent state, the appropriate package halt scripts will run to clean things up when the node comes back up. But cmviewcl will continue to show the packages as detached. Either cmhaltpkg or cmrunnonde (1m) will reset the packages' state and status.

282 Cluster and Package Maintenance