topic Re: slow network performance from a virtual in Operating System - Linux

slow network performance from a virtual

BradV — Fri, 18 Feb 2011 13:30:25 GMT

I have some BL460CG6's in a c7000. I have RHEL 5.5 installed on the blades. The blades have dual port Flex-10 NICs and I have two Flex-10 switches in interconnect bays 1 and 2. I have the server in slot 5 set up as a kickstart server. I did a PXE kickstart installation of two KVM servers on the server in slot 1. The installs ran without a problem and quite fast.

My issue is the network performance after the installation. I have some compressed tar files and configuration scripts that run on each new server. Normally it takes a few minutes on a 100MB network so copy everything over. It took multiple hours to do this on the virtual servers. I'm getting about 5-8 KB/s transfer speed.

Oh, I bridged both virtual servers to eth0.

Any ideas why network performance is so bad or how to improve it?

Re: slow network performance from a virtual

Ragu_3 — Mon, 21 Feb 2011 10:14:05 GMT

Please check your routing table on the main hardware node. Which virtualization setup are you using?

Re: slow network performance from a virtual

Michael Leu — Mon, 21 Feb 2011 20:14:31 GMT

LRO needs to be disabled with bridges. Do you have 'options bnx2x disable_tpa=1' in modprobe.conf? See https://bugzilla.redhat.com/show_bug.cgi?id=518531 and its parent https://bugzilla.redhat.com/show_bug.cgi?id=582367

Re: slow network performance from a virtual

BradV — Wed, 23 Feb 2011 11:26:48 GMT

Sorry for the delayed response, closed Monday for a holiday and yesterday for snow! :)

Adding the modprobe.conf options fixed the problem! My virtual server networks are working very well now. Thanks so much for the help! :)