If you use the intersystem link for host traffic, ensure that you have sufficient
bandwidth to support all sources of load.
Scenario: The hosts in a local clustered system can read and
write to the volumes in a remote system
In this scenario, the hosts in the local
system also exchange heartbeats with the hosts that are in the remote system. Because the
intersystem link is being used for multiple purposes, you must have sufficient bandwidth to
support the following sources of load:
- HyperSwap®
(active-active), Global Mirror, or Metro Mirror data transfers
and the system heartbeat traffic.
- Local host to remote volume I/O traffic or remote host to local volume I/O traffic.
- Local-host-to-remote-host heartbeat traffic. If the local host to remote volume I/O traffic
is allowed to use a high percentage of intersystem link bandwidth, the latency that is seen by
the hosts that access system volumes that are participating in Metro Mirror or Global Mirror operations can
be impacted. The bandwidth congestion can cause the Global Mirror link tolerance
threshold to be exceeded. When the Global Mirror link tolerance
threshold is exceeded, Global Mirror relationships
are stopped.