Dell PowerVault DL2200 CommVault - Manual (Page 6)

Dell PowerVault DL2000 Remote Office Backup Strategy
Page 4
purposes, such as creating additional copies of data, remote restore, tape vaulting (with or without
encryption), content indexing, and enterprise search.
Data on the primary mount path of the replicated disk library continues to be available for local recovery
operations.
Use Cases Not Addressed by DDR
DDR does not replace any existing CommVault functionality or address some other specific use cases.
Automatic Failover between Primary and Secondary Media Agents
DDR in itself does not support the ability to failover between primary and secondary media agents—
replication with DDR is unidirectional. Moreover, the Single-Instance Database (SIDB) is not replicated.
Also, the secondary media agent and mount path is available strictly as a read-only copy for recovery or
for secondary operations. If the secondary mount path is converted to a writeable copy (via mount path
properties), subsequent backups will not be replicated to the first mount path.
Creating Point­In­Time Images of Mount Paths
DDR does not support creating point-in-time snapshots of the disk library, and it does not use drivers to
track and log file system updates. It also does not have the ability to create recovery points. Periodically,
the media agent invokes DDR (default 30 minutes), which then checks the USN on the primary mount
path and determines the files that need to be copied over.
Replacing AuxCopy and Synthetic Full
Remote Single Instance Backup with DDR does not replace AuxCopy. Even though there are two copies
of the data, they have the same retention period. When data aging criteria for the storage policy copy is
met, data from both mount paths is deleted.
Remote Single Instance Backup with DDR does not replace Synthetic Full operations, either. However,
depending on the customer requirements, the frequency of Synthetic Full operations may be reduced,
since there are two copies of the data.
Fan­Out with DDR
DDR does not yet support the ability to replicate the mount paths to multiple destination media agents,
which may not be desirable. DDR copies all have the same retention criteria, and the secondary copies
are read only. If data from the primary mount path is aged, it is also removed from the secondary mount
paths.
The suggested method for creating multiple copies of data is to use DDR to replicate the primary copy to
create two copies of data, and then use AuxCopy to create as many copies as required—each with
different retention criteria. AuxCopy can use the secondary mount path as the source.