General considerations, General system restrictions, General software restrictions – HP 3PAR Operating System Software User Manual
Page 14
General Considerations
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Distance between the systems.
Systems in the same room can be connected through Gigabit Ethernet (GigE) switches,
or through FC networks. Longer distances require other topologies.
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To use remote copy for disaster recovery, the backup storage system should be kept at
a remote site far enough away that the two sites are unlikely to be affected by the same
disaster.
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In synchronous replication mode, the latency of remote-copy writes increases with distance.
•
Bandwidth.
Remote copy over IP (RCIP) configurations can fully use all 1 Gbps links during the
synchronization process. If you use networks with lower throughput, the throughput between
systems running HP 3PAR Remote Copy software might be capped by the network.
•
Connection requirements.
For more information, see
“Setting the Transport Layer” (page 26)
.
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Data availability and speed.
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To maintain availability, you must use more than one link to connect storage systems.
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HP 3PAR Remote Copy requires at least two separate network connections between
storage systems to ensure availability in the event that one of the networks fails. For
optimal availability, the two connections should be connected to separate network
equipment.
◦
When there are multiple physical links between the storage systems, HP 3PAR Remote
Copy uses all the available links that are configured for the same replication mode
(synchronous or asynchronous periodic) to transmit data in parallel.
General System Restrictions
•
All storage systems in the configuration must be configured at the same HP 3PAR Operating
System software level unless otherwise specified in the feature-availability configuration matrix.
To obtain configuration documentation, see the HP Single Point of Connectivity Knowledge
(SPOCK) website:
Under Other Hardware, select 3PAR.
General Software Restrictions
•
HP 3PAR Remote Copy does not support self-mirroring configurations. It cannot use a storage
system to replicate its own primary volumes to itself.
•
HP 3PAR Remote Copy does not support multihop configurations. It cannot replicate a primary
volume group to a backup system and then replicate the volume group again from the backup
system to a third storage system.
•
To limit the potential for data loss, HP recommends that synchronous mode replication be used
whenever the additional write latency induced by the network, plus the write latency induced
by the target array, will not exceed the maximum write latency tolerable by the application
whose data is being replicated.
NOTE:
In synchronous mode replication, the maximum network latency supported is 2.6 ms
round trip.
14
Planning Your Remote-Copy Setup Strategy