If you use the intercluster link for
host traffic, ensure that
you have sufficient bandwidth to support all sources of load.
Scenario:
The hosts in a local cluster can read and write
to the VDisks in a remote cluster
In this scenario, the
hosts in
the local cluster also exchange heartbeats with the hosts that are
in the
remote cluster. Because the intercluster link is being used for multiple
purposes,
you must have sufficient bandwidth to support the following sources
of load:
- Global Mirror or Metro Mirror data transfers and the SAN Volume Controller cluster
heartbeat traffic.
- Local host to remote VDisk I/O traffic
or remote host to local VDisk
I/O traffic.
- Local host to remote host heartbeat traffic.
If the local host to remote
VDisk I/O traffic is allowed to consume a high percentage of intercluster
link bandwidth, the latency seen by the hosts that access SAN Volume Controller VDisks
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.