What is a replica?

Published : April 8, 2005 | Updated : August 17, 2005

In Data Protection Manager (DPM), a replica is a complete copy of the protected data on a single volume. A replica contains all the properties of the volume, including local shadow copy settings, security settings, and sharing. When a protection group is created, a replica is created for each protected volume in the protection group.


When you protect a data source that contains a mount point, the mount point itself is not replicated; you must manually recreate the mount point when you recover the data.

Before DPM can start protecting the data sources in a protection group, a replica of the data must be created in the storage pool on the DPM server. After a replica is created for each protected volume, changes to the protected data are transferred to DPM incrementally through synchronization, according to a set schedule.

To create a replica on the DPM server, you can either have DPM copy the data from the file server over the network or you can manually create a replica from a tape backup or other removable storage medium. Replicating the data over the network requires no intervention, but it can take several hours, depending on network bandwidth and the data size. To minimize the impact on network bandwidth, you can schedule replication for a time when network traffic is low.

If your data is backed up on tape, you can manually create a replica on the DPM server from the tape. This method does not affect network bandwidth, and can save time if you are transferring large amounts of data. However, you must manually copy the data to the DPM server and then manually synchronize the replica with a consistency check before scheduled synchronization and shadow copy jobs can begin.

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