Intersite link planning

Specific intersite link requirements must be met when you are planning to use IP partnership for remote copy.

If you use IP partnership, you must meet the following requirements:
  • TCP ports 3260 and 3265 are used by systems for IP partnership communications; therefore, these ports need to be open.
  • The maximum supported round-trip time between systems is 80 milliseconds (ms) for a 1 Gbps link.
  • The maximum supported round-trip time between systems is 10 milliseconds (ms) for a 10 Gbps link.
  • For IP partnerships, the recommended method of copying is Global Mirror with change volumes.

    This method is recommended because of the performance benefits. Also, Global Mirror and Metro Mirror might be more susceptible to the loss of synchronization.

  • The amount of intersite heartbeat traffic is one megabit per second (Mbps) per link.
  • The minimum bandwidth requirement for the intersite link is 10 Mbps. However, this requirement scales up with the amount of host I/O that you choose to do. Figure 1 describes the scaling of host I/O.
    Figure 1. Scaling of host I/O
    Scaling of host I/O

    The equation that can describe the approximate minimum bandwidth that is required between two systems with <5 ms round-trip time and errorless link follows:

    Minimum intersite link bandwidth in Mbps > Required Background Copy in Mbps + Maximum Host I/O in Mbps + 0.125 Mbps heartbeat traffic

    Increasing latency and errors results in a higher requirement for minimum bandwidth.