leeb_russell
2 Bronze

Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Hi to everyone on the wonderful Equallogic forums 🙂

We have an EQL PS4100X running VM's on vSphere 5.1. Everything is working great and we're about to migrate our main production database to a SQL 2012 VM. I've been doing some research on whether we should enable jumbo frames on the VMXNET3 adapter in the VM.

From reading this white paper it seems there are major performance advantages to enabling jumbo frames and some other options within the NIC settings:

http://en.community.dell.com/techcenter/extras/m/white_papers/20403565.aspx

Just curious as to what other people do and if they've seen any improvement in performance. Anyone had any experience with this ?

Thanks

Lee

Tags (2)
0 Kudos
1 Solution

Accepted Solutions

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Jumbo frames being good or bad, depends heavily on the switching infrastructure.   If the switches are not sufficient to handle jumbo frames and flowcontrol, then performance could be worse with Jumbo frames enabled.

If the switches are not on the certified list for EQL arrays,  I tend to start with standard frames, get a baseline run, then try Jumbo Frames incrementally and make sure things don't get worse.

Jumbo Frames can provide a benefit, it will never be a huge increase, but it does improve the network efficiency and might reduce CPU overhead.    That are not a requirement for EQL iSCSI environments.

 Please check out the best practices with ESX document.  That can really help maximize your performance with EQL storage.

http://en.community.dell.com/techcenter/extras/m/white_papers/20434601.aspx

 Regards,

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

8 Replies

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Jumbo frames being good or bad, depends heavily on the switching infrastructure.   If the switches are not sufficient to handle jumbo frames and flowcontrol, then performance could be worse with Jumbo frames enabled.

If the switches are not on the certified list for EQL arrays,  I tend to start with standard frames, get a baseline run, then try Jumbo Frames incrementally and make sure things don't get worse.

Jumbo Frames can provide a benefit, it will never be a huge increase, but it does improve the network efficiency and might reduce CPU overhead.    That are not a requirement for EQL iSCSI environments.

 Please check out the best practices with ESX document.  That can really help maximize your performance with EQL storage.

http://en.community.dell.com/techcenter/extras/m/white_papers/20434601.aspx

 Regards,

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

leeb_russell
2 Bronze

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Sorry, should have mentioned we have 2 stacked DELL Powerconnect 6224 switches!

Thanks very much for the info Don. I'll check out the best practices document and may tinker with Jumbo frames down the line.

Cheers

Lee

0 Kudos
Highlighted

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

re: Switches.  Make sure you are at most current FW.  Which I believe is 3.3.3.5.  For jumbo frames, if you haven't already done so, create a VLAN for all ISCSI connections.  Both server and array.  This will insure that Jumbo frames are properly passed vs. using the default VLAN.   Also when setting the MTU size, set it to 9216, not 9000 on the switch.

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

0 Kudos
leeb_russell
2 Bronze

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Thanks for the info. We're not on the latest firmware. I'm a bit wary of updating the firmware on the switches in case the config is lost, but I know we have a backup of it. The switches were configured by DELL engineers who created a VLAN for the iSCSI connections. Interesting about the MTU. It's been configured to 9000 on the switch. Should it be 9216 on just the switch ? Should we set it to 9216 on the ESXi hosts as well ?

0 Kudos

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Re: Firmware.  it's definitely a really good idea to upgrade that.   I suggest setting the proper MTU size then re-save the configuraiton.

re: 9216.  With the PowerConnect setting to 9000 doesn't allow for the overhead.  So "9000" really needs to be at least 9014.   On the EQL array, Windows and ESX "9000" allows for that overhead.  Since 9216 is the max on the switch we suggest setting it to max.   The intiaitor and array will negotiate down to match MTU sizes.  

Regards,

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

0 Kudos
leeb_russell
2 Bronze

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Thanks Don, makes sense.

0 Kudos

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Glad to help!

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

0 Kudos

RE: Enabling Jumbo Frames on VMXNET3 adapter in Windows Server 2012

Jump to solution

Sorry, if I'm stating obvious, but don't forget to make sure the vSwitch is set for Jumbo Frames, otherwise it won't allow Jumbo Frame negotiation.

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

0 Kudos