HP D2D D2D Best Practices for VTL, NAS and Replication implementations (EH985- - Page 52

What to replicate

Page 52 highlights

Replication overview What to replicate D2D VTL replication allows for a subset of the cartridges within a library to be mapped for replication rather than the entire library (NAS replication does not allow this). Some retention policies may not require that all backups are replicated, for example daily incremental backups may not need to go offsite but weekly and monthly full backups do, in which case it is possible to configure replication to only replicate those cartridges that are used for the full backups. Reducing the number of cartridges that make up the replication mapping may also be useful when replicating several source libraries from different D2D devices into a single target library at a data center, for example. Limited slots in the target library can be better utilized to take only replication of full backup cartridges rather than incremental backup cartridges as well. Configuring this reduced mapping does require that the backup administrator has control over which cartridges in the source library are used for which type of backup. Generally this is done by creating media pools with the backup application then manually assigning source library cartridges into the relevant pools. For example the backup administrator may configure 3 pools: Daily Incremental, 5 cartridge slots (overwritten each week) Weekly Full, 4 cartridge slots (overwritten every 4 weeks) Monthly Full, 12 cartridge slots (overwritten yearly) Replicating only the slots that will contain full backup cartridges saves five slots on the replication target device which could be better utilized to accept replication from another source library. 52

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52
Replication overview
What to replicate
D2D VTL replication allows for a subset of the cartridges within a library to be mapped for replication rather than
the entire library (NAS replication does not allow this).
Some retention policies may not require that all backups are replicated, for example daily incremental backups
may not need to go offsite but weekly and monthly full backups do, in which case it is possible to configure
replication to only replicate those cartridges that are used for the full backups.
Reducing the number of cartridges that make up the replication mapping may also be useful when replicating
several source libraries from different D2D devices into a single target library at a data center, for example.
Limited slots in the target library can be better utilized to take only replication of full backup cartridges rather
than incremental backup cartridges as well.
Configuring this reduced mapping does require that the backup administrator has control over which cartridges
in the source library are used for which type of backup. Generally this is done by creating media pools with the
backup application then manually assigning source library cartridges into the relevant pools. For example the
backup administrator may configure 3 pools:
Daily Incremental, 5 cartridge slots (overwritten each week)
Weekly Full, 4 cartridge slots (overwritten every 4 weeks)
Monthly Full, 12 cartridge slots (overwritten yearly)
Replicating only the slots that will contain full backup cartridges saves five slots on the replication target device
which could be better utilized to accept replication from another source library.