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25 PS Series Asynchronous Replication Best Practices and Sizing Guide | BP1012
6.8 Pool configuration effects
The configuration of groups and pools may also have an effect on how quickly replication occurs. For
example, the number of array members in a pool affects how many array members a volume may be
distributed across. Because of the scale-out architecture of PS Series arrays, a group that contains multiple
members has the potential to move data faster than a group with only a single member. However, if a slow
link (slower than the SAN) exists between replication partners, then the performance impact of the link
bandwidth will override any benefit that having multiple pool members provides. The test results in Figure 12
illustrate this behavior. When replicating across 1 Gb/s or 10 Gb/s links, there was a significant decrease in
time to complete replication when the volume is hosted on a three-member pool when compared to a single-
member pool. As the network bandwidth between replication partners decreases, the difference becomes
negligible.
Effect of number of pool members on time to complete replication
1
10
100
1000
10000
10Gb 1Gb OC3
(155 MB/s)
T3
(45 MB/s)
T1
(1.5 MB/s)
Minutes
Link speed
Time to complete replication: single-member and three-member pool
1-member pool 3-member pool