What is the significance of online to this controller

[jkirti]

This question is with respect to the Compaq StorageWorks array. When we execute cli command show <unit name>, it gives us the LU detail and also shows online to which controller.
In case of Multiple bus failover the LU can be seen on both
the ports of both the controllers,then what is the meaning of LU is &quot;Online to this controller&quot;.

 

[terry712]

you mean you are getting something like this

State:
ONLINE to this controller
Not reserved
PREFERRED_PATH = THIS_CONTROLLER
Host Based Logging NOT Specified
Size: 213291762 blocks
Geometry (C/H/S): ( 41987 / 20 / 254 )

instead of something like this

ONLINE to the other controller
NOPREFERRED_PATH
Host Based Logging NOT Specified

how many fibre hba's in the server?
how many fibre switches?

 

[jjjon]

It means that the disk is being controlled by the particular controller you are logged onto (controller 1). If you logged onto controller 2, you would see 'ONLINE to the other controller' as TERRY712 says.

If the disk had to failover to controller 2 for some reason (or forced onto the controller 2 manually) you would see ONLINE to the other controller if you logged onto controller 1.