50mu – about storage

EMC SAN Copy best practices

• Just like with MirrorView ports: don’t use SC ports as host front end ports. Try to use dedicated ports for SC
• Make sure the zoning is correct between the source SAN Copy port and the target SAN Copy port
• Don’t use zones with multiple storage array (initiator) ports in them. Try to use SIST whenever you can: Single Initiator, Single Target so you’re certain there can only be 1 initiator in each zone

Check your SAN!

To check end to end connectivity you can use (Cisco) DCNM to do connectivity testing, but the previous plain “Fabric Manager” also has this feature (see the picture on the right about this helpful pull down option). I found it very helpful to check if there might be communication errors. Particularly on 3rd party switches / routers.

Check Unisphere

To check if a SAN Copy connection is set up properly, use Unisphere and go to the storage group on the target array, right click and choose “SAN Copy Connections”. If zoning is set up properly and both the source and target ports can “see” each other, there should be multiple lines, each containing the SAN Copy enabled ports from the source array.

Also, in the initiator list each SAN Copy enabled port that is correctly zoned to the target array should be visible and registered as a SAN Copy initiator.

Real life trouble

This week I found out that all sessions owned by a Clariion’s SPB suddenly failed and after applying the best practices and cleaning up the zones and connections between source and target the sessions could be resumed.

check your SAN / zones / connectivity. Even though I say it all the time and it’s meant as a little joke:

Rule 1: it’s (almost) always the network

In my case it was the SAN, which is a network too.