dbcc options for high availability systems

rollback_failback

Rolls back the effect of sp_companion... prepare_failback and returns the companion to failover mode. This command works regardless of the results of the prepare_failback command.

dbcc ha_admin (" ", rollback_failback)

Where “ “ is a required empty placeholder.

• Can be used only in failback mode.

• Any failback threads waiting for the resume command are killed when this command is executed.

• You may need to perform platform-specific steps to prepare your companions for the rollback_failback option. See the appropriate chapter in this manual for more information.

• You can issue this command only from the secondary companion.

rollback_failover

Rolls back the effects of fail over from the primary companion, and returns it to normal companion mode. rollback_failover does not affect the secondary companion.

dbcc ha_admin (" ", rollback_failover)

Where “ “ is a required empty placeholder.

• This command can be used only in failover mode.

• You may need to perform platform-specific steps to prepare you companions for the rollback_failover option. See the appropriate chapter in this manual for more information.

• rollback_failover has no effect on the companion server that failed. The companion server that takes over the failed companion’s workload resumes normal companion mode.

• You can issue this command only from the secondary companion.

• This command works even when fail over has marked the databases “suspect.”

drop_failoverdb

Used only in failover mode. drop_failoeverdb drops the failed-over databases that could not be dropped with the drop database command. This command also cleans up the master_companion of all the metadata relating to the dropped database.

dbcc ha_admin (" ", drop_failedoverdb, database_name)

Where " " is a required empty placeholder, and database_name is the name of the database you are dropping.

• Use only as a last resort, when you must drop a database to complete the load of another database.

clusterlock

Acquires or releases cluster-wide locks during a cluster operation.

dbcc ha_admin (" ", clusterlock, [acquire | release])

For more information about cluster-wide locks and releasing them, see “Cluster locks in a high availability node”.

state_machine

Moves the companion server to single-server mode.

dbcc ha_admin (' ', 'state_machine', 'halt')

Where " " is a required empty placeholder. For information about using this option, see Appendix A.

session

Invokes clients that are sleeping because of a failed sp_companion...resume. Clients that are invoked disconnect from the secondary companion and connect to the primary companion.

dbcc ha_admin (SYB_HACMP, session, "drop")