Advantages of Local Continuous Replication Over Traditional Backup Schedules

Se aplica a: Exchange Server 2007

Última modificación del tema: 2007-04-06

Local continuous replication (LCR) is a single-server solution that uses built-in asynchronous log shipping technology to create and maintain a copy of a storage group on a second set of disks that are connected to the same server as the production storage group.

Although LCR provides significant advantages over several backup methods, it does not provide 24 hour a day, every day availability. For details about a Microsoft Exchange Server 2007 replication feature that does provide 24 hour a day, every day availability, see replicación continua de clústeres.

LCR provides log shipping, log replay, and a quick manual switch to a secondary copy of the data. These features reduce the recovery time needed for data-level disasters. LCR also reduces the number of backups that are needed for sufficient data protection. Although LCR does not eliminate the need to make backups, it does reduce the need to make daily, full backups. LCR also enables you to offload Volume Shadow Copy Service (VSS) backups from the active storage group to the passive storage group. All four backup types (Full, Copy, Incremental, and Differential) can be taken from the passive copy locations, preserving valuable disk I/O on the active copy's LUNs to serve clients.

In addition to reducing overall total cost of ownership (TCO), LCR provides additional advantages over the preceding backup solutions. LCR lets you have additional copies of your Exchange databases, which provides you with the following benefits:

• Reduction in database backup frequency   The LCR copy is the first line of defense against a production database failure. Both the production storage group and the storage group copy would have to fail before backup copies would be required. As a result, we recommend a longer service level agreement (SLA) for this case. With a longer SLA, weekly full backups and daily incremental backups are recommended.
• Fast recovery from disasters   Typically, the recovery occurs in less than ten minutes with little or no data loss.
• Support for larger mailbox quotas   This support is achieved as a result of fast recovery that is independent of database size.

For more details and specific guidance for backup and restore, see Recuperación ante desastres.

Exchange Backups and LCR

Exchange-aware backups are supported from active storage groups and databases and from passive database copies.

Exchange-aware backups in this configuration can either be performed using streaming or VSS backup solutions. While streaming backups can be performed only from the active copy, VSS backups can be made from either the active or the passive copy.

Exchange Restores and LCR

Exchange-aware restores can either be performed using streaming or VSS backup solutions. Restores can be targeted to the active database and log file locations. Exchange-aware restores of database backups directly to the passive copy location is not supported natively. Restores to passive copy locations can be achieved manually by a file-level restore.

For More Information

For more information about LCR, see Replicación continua local.