HP Veritas Volume Manager 5.0 -UX 11i v3 manual Multiple host failover configurations, Node abort

Administering cluster functionality

Multiple host failover configurations

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Note: Once shutdown succeeds, the node has left the cluster. It is not possible to access the shared volumes until the node joins the cluster again.

Since shutdown can be a lengthy process, other reconfiguration can take place while shutdown is in progress. Normally, the shutdown attempt is suspended until the other reconfiguration completes. However, if it is already too far advanced, the shutdown may complete first.

Node abort

If a node does not leave a cluster cleanly, this is because it crashed or because some cluster component made the node leave on an emergency basis. The ensuing cluster reconfiguration calls the VxVM abort function. This procedure immediately attempts to halt all access to shared volumes, although it does wait until pending I/O from or to the disk completes.

I/O operations that have not yet been started are failed, and the shared volumes are removed. Applications that were accessing the shared volumes therefore fail with errors.

After a node abort or crash, shared volumes must be recovered, either by a surviving node or by a subsequent cluster restart, because it is very likely that there are unsynchronized mirrors.

Cluster shutdown

If all nodes leave a cluster, shared volumes must be recovered when the cluster is next started if the last node did not leave cleanly, or if resynchronization from previous nodes leaving uncleanly is incomplete.

Multiple host failover configurations

Outside the context of clustering functionality, VxVM disk groups can be “imported” (made available) from only one host at any given time. When a host imports a disk group as private, the volumes and configuration of that disk group become accessible to the host. If the administrator or system software wants to privately use the same disk group from another host, the host that already has the disk group imported (importing host) must “deport” (give up access to) the disk group. Once deported, the disk group can be imported by another host.

If two hosts are allowed to access a disk group concurrently without proper synchronization, such as that provided by the Oracle Parallel Server, the configuration of the disk group, and possibly the contents of volumes, can be