topic Re: P4500 NIC Settings in StoreVirtual Storage

P4500 NIC Settings

xim94 — Thu, 24 Mar 2011 11:16:53 GMT

Hello all, I am working on setting up my first LH san. I understand that using flow control on your NICs/switches is the best practice. I also am told I should plan on setting up jumbo frames.

I see no mention that these two options are mutually exlusive on the LH side, but they are explicitly identified as mutually exlusive in the HP Procurve manual; which says to disable any flow control settings on vlans that will use jumbo frames.

So, can anyone help guide me on the design here? which is more important? We will be using the LH to hold all of our vmware vms, as well as our sql & domino databases

Thanks all
Matt

Re: P4500 NIC Settings

Alex Ball — Thu, 24 Mar 2011 12:08:24 GMT

I have always enabled both flow control and jumbo frames when using iSCSI, this has been on Cisco and HP switches.

I have never heard of them being mutually exclusive.

Perhaps its specific to your switch.

Re: P4500 NIC Settings

Jitun — Thu, 24 Mar 2011 13:30:56 GMT

I would recommend Flow Control Enabled throughout the SAN.
Jumbo Frames do not result in any appreciable increase in performance.
Jumbo frames will be of not much help with smaller IOs.

So my recommendation keep Flow Control ON and Keep Default Packet size.

Re: P4500 NIC Settings

xim94 — Thu, 24 Mar 2011 14:34:55 GMT

We have Procurve 2848s.

Straight from the manual (pg 10-22) - "The switch does not allow flow control and jumbo packet capabilities to co-exist on a port."

I won't be able to replace the switches with something newer (assuming that restriction is not applicable to higher end switches) for a while; so I will start will flow control, and worry about jumbo packets later.

unless someone else has a better idea.
thanks again.

Re: P4500 NIC Settings

Alex Ball — Fri, 25 Mar 2011 13:26:25 GMT

I have to agree with the previous comments, go with flow control, I have never found JUMBO frames makes that much difference.

Re: P4500 NIC Settings

Aaron Curto — Sun, 27 Mar 2011 13:58:33 GMT

Check the newest version of the Management and Configuration Guide for your switch. Some earlier versions of the guide incorrectly stated Jumbo Frames and Flow Control could not be enabled at the same time.

Re: P4500 NIC Settings

Mark... — Mon, 28 Mar 2011 07:46:42 GMT

Hi,
I would suggest that you read this HP document on the P4000 as it will probably answer a few of your questions.

http://h20195.www2.hp.com/v2/getdocument.aspx?docname=4AA2-5615ENW.pdf

Mark...