HP 12000 Design Manual page 21

Figure 8 Replication Configuration Options
Active-Passive: The best deployment for a single site disaster recovery protection. The active
source device receives the local backup data and then replicates it to a passive target device
at the disaster recovery site dedicated to receiving replication data.
Many-to-one: The best deployment for several smaller sites consolidating their replication to
a central disaster recovery site. Each source device in the smaller sites replicate to a central
target device which you configure to have multiple sources replicate to a common virtual
library on the central device (each source replicates to its own subset of the cartridges in the
virtual library). Alternatively, each source can have its own dedicated virtual library. Up to
four remote VLS sites can copy to a single HP VLS at the central site at launch, and this will
be increased over time. Up to 16 remote D2D sites can copy to a single D2D4000 at the
central site, and up to 24 remote D2D sites can copy to a D2D4100.
Active-Active and N-Way: The best deployment for sharing your VLS or D2D system hardware
for both receiving backups and receiving replication data (so each device is both a source
and a target as shown in the above diagram). Active-active is one way to implement
cross-replication between sites, but you can use two active-passive deployments to achieve
the same result. Choosing between either active-active or 2x active-passive deployments for
cross-replication depends on which provides the lowest cost. Active-active is only recommended
if the backup traffic on each device is only using up to half of the device's maximum
performance and capacity, because you need additional performance and capacity for the
replication target operations.
For example, if you have two VLS9000 sites that each requires 2-nodes/2-arrays for just their
backup performance/capacity and 2-nodes/2-arrays for their replication target
performance/capacity, then you have the following choices for cross-replication deployment:
◦ Active-Active: Each site requires a 4-node/4-array VLS9000 (with deduplication) shared
between backups and replication target, one rack, and four replication LTUs.
2x Active-Passive: Each site requires a 2-node/2-array VLS9000 (with deduplication) for
◦
backup and a separate 2-node/2-array VLS9000 (with deduplication) for replication
target, two racks, and two replication LTUs.
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