HPE EVA Storage

Sanity check on SAN switch reconfig (pidformat)

 
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Graham Allan
Advisor

Sanity check on SAN switch reconfig (pidformat)

I have a small SAN of three Brocade 3800 switches to which we now want to add Brocade 4100. The obvious problem is that the existing switches are running with pidFormat=0 which is incompatible with the 4100.

I believe what I have to do is:

1) shut down all servers on the SAN, as the changes are going to be disruptive.
2) on each 3800 switch, run "switchdisable", "configure", change pidFormat to 1, then "switchenable".
3) restart everything.

which isn't so bad. I wanted to check here in case I am missing anything.

Thanks for any advice,

Graham
5 REPLIES 5
Mark Poeschl_2
Honored Contributor
Solution

Re: Sanity check on SAN switch reconfig (pidformat)

Normally there would be redundant fabrics which would allow one to switch them over one at a time, but that doesn't sound like it's the case here. So yes, if you've only got one fabric with 3 switches (soon to be 4) you'll have to take the whole thing down to accomplish the PID format change.
Uwe Zessin
Honored Contributor

Re: Sanity check on SAN switch reconfig (pidformat)

Altering the PID format means that all 24-bit Fibre Channel addresses (PID, N_Port ID, ...)assigned by the switch change. It is transparent for most operating systems except for older version of HP-UX (not sure about V3) and IBM AIX.
Tru64 Unix uses 'persistent LUN binding' which is not affected by an FC address change.
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Graham Allan
Advisor

Re: Sanity check on SAN switch reconfig (pidformat)

Thanks, our hosts on the SAN are Tru64, Windows 2003, Linux and FreeBSD. Tru64 really seems like the only one which accomplishes persistent mapping in a sensible way; our linux and FreeBSD boxes are just restricted with zoning and then mount their disks using ufs or ext3 volume labels. I think this means they shouldn't be affected by addressing changes either...
Uwe Zessin
Honored Contributor

Re: Sanity check on SAN switch reconfig (pidformat)

Correct.

HP-UX for example forms a pretty complex hardware path:
disk 3 0/7/1/0.6.4.0.0.0.1 sdisk CLAIMED DEVICE HP HSV200
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Graham Allan
Advisor

Re: Sanity check on SAN switch reconfig (pidformat)

Thanks for your help!