Enabling DISP recovery generally avoids manual resynchronization of the datastores.
DISP recovery works with multiwrite replication by handling all recovery operations. In effect, fast multiwrite is used during uptime and DISP is used only for recovery after a downtime.
DISP recovery has the following advantages:
Updates are calculated from the original datastore, not queued in memory. This means that recovery can survive restarts of a master (although you can lose the in-memory queues).
Resynchronization uses state-based updates. When there are a large number of replays, this is more efficient than replay-based recovery.
DISP processing supports automatic conflict resolution using a last-write-wins rule. Managing conflicts is often a problem for replay-based systems because the order of updates from different masters can be critical.
Note: DISP recovery uses the highest authentication level that is available. Only specify the use of SSL authentication level (ssl-auth in a knowledge file) if you have set up the necessary SSL certificates for the DSAs in the region.
Copyright © 2009 CA. All rights reserved. | Email CA about this topic |