11-22-2017 06:34 AM
i have i have 2 6510's to replace. my clients are configured with dual channels to the data source. if i place a 6510 into disabled mode will the clients gracefully migrate to the other leg?
11-22-2017 07:27 AM
That depends. Generally speaking, the answer is yes. When you perform the command 'switchdisable' all ports are disabled, and there is no graceful port transmit termination. You may(likely will) lose frames which are in flight at the time of the port shutdown. However, all the traffic will flow to the storage from host through the other switch, provided you have configured the switch to handle the data traffic correctly.
There are a number of path management software packages that customers use to insure redundant fail-over should a path fail. If you are not using one of these (MPIO, APF), and are relying on the HBA driver to handle lost transmissions, faultless path loss cannot insure there is no data loss. Path failover, mirroring paths, load balancing, and other methods of redundant control are answered in the IBM redbook: IBM SAN Survival Guide, but of course is IBM specific, although the concept apply to any SAN.
A better course of action would be to disable the path from the server for one side of the fabric(switch) first, to insure that the host does not use that path. Once that is done, disable any ISLs, and then perform the 'switchdiable', and replacement.
Don't forget to save your switch configureat with 'configupload' to a safe file location so that you can load the existing config on the new switch.