topic Re: Disable Jumbo Frames in Array Setup and Networking

Disable Jumbo Frames

pswiatek119 — Mon, 26 Oct 2015 20:03:16 GMT

If we want to disable Jumbo Frames on our arrays, what kind of disruption are we looking at?

We've expanded our iSCSI network past the interconnect switches on our HP c7000 chassis, and we are having issues with the Cisco out 3120X and Brocase ICX-6610 switches talking reliably.

Our 10GB links are no where close to being saturated, so we do not feel like having Jumbo frames enable are worth the headache.

Cheers,

Re: Disable Jumbo Frames

bgrieve65 — Mon, 26 Oct 2015 22:05:59 GMT

Paul,

I would recommend discussing this with Support before proceeding. You may want to schedule this for a time window where you can afford an outage. I've seen different behaviors in different environments when frame sizes don't match, and since you will be changing the configs on the switches & array at different times (even if it's only a few minutes apart), you could see the hosts drop connections. Also, I believe many switches require a reboot when changing this config.

Good luck!

Re: Disable Jumbo Frames

Valdereth — Tue, 27 Oct 2015 12:28:44 GMT

In the very least - count on the Nimble array interfaces going through a brief reset. I enabled JF on a Nimble Array recently and we got notification from the vSphere Hosts of a drop in connection but it was so brief that there was no noticeable interruption in service to the VMs.

Re: Disable Jumbo Frames

pswiatek119 — Wed, 28 Oct 2015 17:20:10 GMT

We've spoken to support.

And the consensus is the as long as the our ESXi cluster is already set to 1500 MTU, then we should only see a brief outage as the interface reconfigure.

We will schedule the change of an upcoming maintenance window and see what happens.

Re: Disable Jumbo Frames

Valdereth — Wed, 28 Oct 2015 18:18:48 GMT

Provided your Hosts are configured properly, I'm sure you'll be fine. You know how it is though.. we've got to prepare for the worst!