Steps to move WINNT host to different switch in same fabric

Question

I have 2 fabrics each with 2 DS16B2 switches and 1 DS220B switch. I have 2 WINNT hosts (one is a MSCS cluster server). Both hosts are running PowerPath 5.1.1 with 2 paths each. Each path is connected to one of the DS220B switches in each fabric. I need to move the hosts from the DS220B switches to one of the DS16B2 switches in the same fabric (the DS220B switches are EOSL and need to be retired). The hosts run critical 24/7 applications. What steps do I take to move these hosts without application/host outages?

Allen Ward · Accepted Answer

The first question I would ask is how you do Zoning in your fabrics. Do you use WWN zoning or Port zoning.

If you do WWN zoning (and haven't implemented any security features tying the WWNs to specific ports) then this will be dead simple:
- Check Powerpath on the host to ensure that both paths are working
- Move one of the host cables from the old switch to the new one
- Check Powerpath again to make sure that the path picked up and is working again
- Move the other host cable from it's old switch to the new one (in the other fabric)
- Check Powerpath again to make sure that both paths are working again as expected

If you use Port zoning you would need to add a step at the beginning and one at the end:
- BEFORE* add the new ports on the new switches to the zones for that HBA in each fabric
- AFTER* remove the old ports on the old switches from the zones for that HBA in each fabric

Either way, you are lucky to be doing this with Windows. If this was AIX or HP-UX there would be another whole set of steps to discover new paths and clean up dead paths. Windows does not have this problem. You should be able to complete the entire process online without the applications being aware you did it.

rahartzell · Answer

Thanks. I use WWN zoning and your steps are pretty much what I figured but I wanted to make sure. Is the same procedure valid for the MSCS cluster host or do I need to move all of the cluster services to another server in the cluster and shutdown the server I'm moving?

By the way, I have moved AIX hosts as well, but we were able to schedule outages to shutdown the hosts and move the connections and reboot, thus avoiding any AIX cleanup. The Windows hosts are a different story because of the uptime requirements.

Allen Ward · Answer

BTW - I don't want to sound like I'm begging for points or anything, but I did want to point out that it is a "best practice" to tag answers as helpful or correct if you find them so. I know you are new to the Forums, so I thought I would point it out here since you are probably still getting used to the format. This is more important in longer threads as it helps other users quickly pick out the posts that were most relevant to resolving a question, but it is good in smaller threads (like this one) as well as it helps boost the "reputation" of members who participate in answering questions.

And by all means, if you don't feel either option (helpful or correct) is appropriate, don't tag the answers.

Allen Ward · Answer

I can't tell you for sure about the MSCS Cluster host. We don't have any MS Clustering in our environment so I have no experience there. But based on the way Windows handles the pathing, I would be surprised if the clustering made a difference.

RRR · Answer

So you're begging.....

RRR · Answer

hehehe, begging is my department

smw61811 · Answer

*laugh*

rahartzell · Answer

I held off marking your reply as correct until I actually performed the magic. Your information worked perfectly for both the WINNT and the WINNT/MSCS servers. Thanks so much.

Allen Ward · Answer

I'm glad to hear it worked for the cluster too. That was the one piece I couldn't be sure about.

No problem, and I hope you get more opportunity to participate actively in the Forums over the next while!

Allen Ward · Answer

In a very helpful kind of way... Yes

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Steps to move WINNT host to different switch in same fabric

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