Imagine two VIO servers, each with at least two FC adapters and a data center with two SAN “fabrics” accessed through two SAN switches. There is a number of possibilities what “fabric/switch” each FC adapter is connected to. For example:
FCa of VIOS1 could be attached to switch A while FCb of the same VIO server is attached to switch B.
FCc of VIOS2 could be attached to switch A while FCd of the same VIO server is connected to switch B.
Somebody else could have it reversed. Someone else could have both VIOS1 FC adapters attached to Switch A and the other two adapters connected with Switch B. …. . Let’s end the speculations.
What I want to show in this post is how to change the relationship between the physical FC adapter of a VIO server and its virtual FC adapter. One may ask why? Well, last Friday I logged in to a “new” VIOS server and without spending a minute or two to “learn” the “exiting method” used to connect Physical/Virtual adapters, I ended up with two partitions which virtual FC adapters were connected to the same fabric. Oops indeed! Why this is not good? If a host mirrors data, it is better that the disks/mirrors are from different fabrics so when access to one fabric is lost the volume group or groups are still on line because LVM has access to the other mirror (other fabric) – assuming of course, that each volume group quorum requirement is OFF.