Tuesday, October 19, 2010

Upgrading an N7 to S8

We recently upgraded one of our core switches in the data center. Since not everyone gets to see this type of work done, we thought we would share what we did and how a change like this typically goes.

We had a lovely Enterasys N7 chassis and it has served us well, but we were running out of ports and needed to expand our iSCSI storage, so time to go to S. Plus we need 10Gb ports but didn’t have any more room in the N for more blades.

The first step is of course removing the N. The first thing to do is to remove all the blades. These things are
heavy and there’s not much room to have a bunch of people trying to help. Lightening the load is the only real way to do it. They do make a fancy lift that can slide in between the rails and lift it for you. We don’t have one, so we manually do it. Remove the power supplies too....

One of the challenges is that the N7 was 7 blades vertically and the S is using 2 blades horizontally. The trick we found was to split the cables based on the blade, before you put the new S8 chassis in the rack. It’s also a good time to re-label all the cables, if you need to.

But once this is done it’s a lot easier. The trick is to take the cables that go into the bottom blade and run them through the lower opening and the ones for the top through the top opening.

Since the cables are already split the top half of the cables go in the top blade and the bottom go in the lower blade. It just makes it easier to find the right cable when you need it. We did need to re-run 20 or so cables since they were too short. It’s one of the problems with the direction of the blades changing. We might just start using 20 foot cables instead of 15’s.

Typically it takes 5 minutes to run the cable, label, it, connect it in and make it look clean, per Ethernet cable. Power cables are 2 minutes but that’s because they are shorter and usually a lot less of them to have to try and straighten out. Really they do take that long. I questioned it once and they made me cable a rack. It took me that long and it still looked awful. You can do it quicker, but it will look awful and be harder to manage and troubleshoot.

Once all the cables are in, it’s just a little cleanup on them to make them look good and we are done.

Total time to actually do the work was about 5 hours. There’s a lot more time that goes into planning, verifying the documentation is correct and updating it when you are done, Total time including that was closer to 1 week.
I've got pictures, but they didn't seem to want to post today. If you are interested, let me know. I'd be glad to share that with you.

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