How to replace a Nexus 2224 Fabric Extender

[virtuallymikeb]

We have a production 2224 FEX attached to a Nexus 5020.  A power supply has gone bad in the FEX and we've received a replacement 2224.  Again, the 5020 and 2224 are configured and in production.  How do we replace the 2224?  So, the hardware installation is no issue.  We can do that.  We also performed the initial configuration and setup of the entire Nexus environment.  But what, exactly, is needed to replace a production FEX?  Do we treat it as a brand new FEX installation and configuration or is there a partial re-configuration needed to replace the FEX?  I assume replacing a FEX is not just a hardware replacement.  There must be a minimum configuration to replace it.

Thanks!

VirtuallyMikeB

Virtualization Implementation Engineer

Blog: http://VirtuallyMikeBrown.com

Twitter: http://twitter.com/#!/VirtuallyMikeB

LinkedIn: http://linkedin.com/in/michaelbbrown

[virtuallymikeb]

As a clarification, the problem with the fabric extender is not a bad power supply.  From what I hear, half the ports went bad.

[graham-lewis · Accepted solution]

Hi Michael,

We have 5596 switches but I assume the procedure is the same. The FEX are plug and play - they download an image from their parent switch so it really is as simple as unplugging the faulty FEX and replacing it with the new one. It takes a few minutes for the new FEX to come up. I've done it a couple of times with no issue.

Regards,

Graham

[virtuallymikeb]

Hi Graham,

Thanks for the quick reply.  There's no reboot of the 5020 required to recognize the new FEX?  I'll be to the site in a few days and look forward to giving it a try.  I'll give your reply credit when I confirm it.  Thanks!

All the best,

VirtuallyMikeB

Virtualization Implementation Engineer

Blog: http://VirtuallyMikeBrown.com

Twitter: http://twitter.com/#!/VirtuallyMikeB

LinkedIn: http://linkedin.com/in/michaelbbrown

[graham-lewis]

No problem Michael.

Just re-read your 2nd post about half the ports going down and wondered how you have "pinning max-links" configured and whether one of your uplinks may have gone down. If you have 2 uplinks (the maximum for a 2224) and pinning max-links set to two, then (as I understand it) if one of you uplinks goes down, half the ports will be disabled. We use pinning max-links 1 and port-channels so have never experienced this but it may be worth checking.

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/command/reference/rel_4_0_1a/fex-cmd-ref.html#wp1584218

Regards,

Graham

[virtuallymikeb]

Hi Graham,

I'm familiar with the pinning max-links configuration.  Our design includes a port-channel for the FEX-to-5020 uplink and uses pinning max-links 1 as required for a port-channel.  However, a different team implemented this particular site, performed the troubleshooting, and ordered the replacement FEX.  I'm not sure what the current config looks like, but I agree, that if it's configured for pinning max-links 2 and there was a failure somewhere in the uplink, that half the ports would be isolated.  I'll post an update when I get to the site and figure out what's going on.  Thanks so much for the replies.

All the best,

VirtuallyMikeB

Virtualization Implementation Engineer

Blog: http://VirtuallyMikeBrown.com

Twitter: http://twitter.com/#!/VirtuallyMikeB

LinkedIn: http://linkedin.com/in/michaelbbrown

[virtuallymikeb]

Hi Graham,

It certainly was as easy as you said - a simple plug-and-play operation.  Of course, to verify everything was working as expected, the show fex command was very useful.  We could see the image download and then the FEX come online.  The status LED on the back of the FEX coincided with the image download and turned green when the FEX finally came up.  Thanks for all the responses.

Also, the pinning max-links was set correctly: pinning max-links 1.

All the best,

Mike