topic Re: Recabling VA7410 in Disk Enclosures

Recabling VA7410

Ron Levy — Thu, 02 Jan 2003 18:37:04 GMT

Just as a sanity check:
I have a VA7410 attached to two production L2000 machines.
Machine 1 has two fibre channel cards. The first goes to 'host 1' on 'controller 1' on the VA7410, and the second goes to 'host 2' on 'controller 2'.
Machine 2 has two fibre channel cards. The first goes to 'host 1' on 'controller 2' on the VA7410, and the second goes to 'host 2' on 'controller 1'.

This VA7410 is not currently in use. I have LUNs configured on it but the machines it is connected to have no volume groups or logical volumes or such pointing to it. They are, however, production machines and cannot lightly be taken down.

I have been told that there is an 'affinity', that hooking to host1-controller1 is a faster pathway to Redundancy Group 1 on the VA7410. So I hooked Machine 1 up with that path.

Well, plans changed and now it looks like we should have Machine 2 hooked to host 1-controller 1 (with the obvious switches taking place from there.)

Are those fibre cables safely hot-pluggable? Given that I am not actively using that VA, can I just swap around the cables and then run an appropriate ioscan to scope out the aray and find the hardware pathways to the new LUNs?

Thanks,
-Ron Levy

Re: Recabling VA7410

Steven E. Protter — Thu, 02 Jan 2003 18:41:05 GMT

I work with an array built by another maker, Seagate's Xiotech.

We have been able to make switches such as you plan without taking the servers offline.

The critical piece is that you have no logical volumes allocated on the disk array.

Drivers have been created in /dev/dsk and you may by making this switch, or by changing the LUN on the array get some EMS messages about missing disks.

Still to be safe, I'd check with support for the disk array. They all work differently.

Steve

Re: Recabling VA7410

Eugeny Brychkov — Thu, 02 Jan 2003 19:20:56 GMT

Ron,
perfomance path for LUNs in RG1 is C1, perfomance path for LUNs in RG2 is C2. If using non-perfomance path then internal bus between VA controllers will be utilized leading to perfomance loss (to so much, but loss).
As soon as you have no VGs on VA and no appications accessing raw physical volumes created on VA LUNs, you can re-attach FC cables. Note that physical paths will change and device files also. So on the old path you will see 'NO_HW' (until server reboot) but new devices will appear on the new paths.
Eugeny

Re: Recabling VA7410

Simon Galton — Fri, 07 Mar 2003 15:15:13 GMT

Ron -- sorry, just noticed this thread after a search.

If it's not too late, here's a suggestion.

If the va7410 is not being used, just decide to swap the LUN assignments! So, if LUN1 is on RG1 and LUN2 is on RG2 just use them as you need to...

Simon