Saturday, February 4, 2012

Advantage and disadvantage of Database Mirroring

Advantages Database Mirroring:
  1. Database mirroring supports full-text catalogs.
  2. Database Mirroring architecture is more robust and efficient than Database Log Shipping. It can be configured to replicate the changes synchronously to minimized data loss.
  3. Does not require special hardware (such as shared storage, heart-beat connection) and clusterware, thus potentially has lower infrastructure cost
  4. Configuration is simpler than log shipping and replication, and has built-in network encryption support (AES algorithm).
  5. It has automatic server failover and client failover mechanism.
  6. Because propagation can be done asynchronously, it requires less bandwidth than synchronous method (e.g. host-based replication, clustering) and is not limited by geographical distance with current technology.
Disadvantages of Log Shipping:

  1. Mirror server/database is not available for user operation.
  2. Potential data lost is possible in asynchronous operation mode. RTO will vary and depend on several factors, such as propagation interval time and bandwidth speed.
  3. Automatic server failover may not be suitable for application using multiple databases.
  4. It only works at database level and not at server level. It only propagates changes at database level, no server level objects, such as logins and fixed server role membership, can be propagated.

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