Administration Guide › Set Up Replication › Multiwrite Replication › How Multiwrite Replication Works › Multiwrite Queues

Multiwrite Queues

If a peer DSA is offline, the sending DSA puts new updates for the peer in a queue, and periodically tries to connect to the peer.

When the peer DSA comes back online, the queued requests are sent in the order that they were processed locally.

While the peer DSA remains offline, the queue grows. The DSA raises an alarm, and writes to the alarm log, at 60%, 70%, 80%, 90%, and 100% of queue capacity.

If the queue becomes full, the peer DSA ignores the unavailable DSA. It discards all the queued requests for the unavailable DSA and temporarily drops it from the multiwrite set. To bring this DSA back into service, you must resynchronize the DSA datastores manually, and restart the DSAs.

If a DSA has attempted a multiwrite operation, the get dsp console command returns one of the following states:

• Failed

  Indicates that the multiwrite DSA is not responding to an update. Updates for that DSA are held in the multiwrite queue until the DSA responds. The queue is retained until the multiwrite queue size is exceeded.

• Recovering

  Indicates that the DSA has become available and still has old updates in its queue.

• OK

  This is the normal multiwrite DSA status.