Friday, January 18, 2008

Dell PowerEdge & Broadcom Issues

For some time now we've been experiencing a problem across the board with Dell PowerEdge 2900/2950 servers equipped with Broadcom Gigabit ethernet cards.  The symptoms usually manifest themselves in the form of slow upload speeds between certain endpoints.  Dell Server to Dell Workstation transfers seem unaffected, however when using non Intel/Broadcome cards (Realtek, for example), upload speeds over a gigabit network come in around 100kbytes/second.  We've also had this problem out to the internet when paired with both Cisco and Dell switches.

Dell Support has been pretty hush on this issue, failing to even admit it is a widespread problem (indeed if you Google about it you'll find lots of complaints).

TOE seems to be to blame and some posters have gone as far to recommend removing the TOE key (the hardware key that enabled the feature) and reinstalling the OS.

Indeed it does appear to be a problem with TOE and Broadcom drivers (among the other issues we have with them, but that's another story).

The good news is that there is a pretty simple fix for this, assuming you are running Windows 2003 SP2 with the Scalable Networking Pack (SNP):

Netsh int ip set chimney DISABLED

This disables TOE offloading, known as "TCP Chimney offload" in Windows.

We've run this on a number of servers now, and in all cases, it has resolved the slow transit issues.

Now only if Broadcom would fix their drivers.

11 comments:

Stephen Flynn said...

I've been having the same trouble. Have you got it to work yet with TOE enabled?

Steven Berkovitz said...

I'm afraid not - Dell refuses to admit this problem even exists and hence, doesn't have any recommendations for getting TOE working without all the problems described.

I have no doubt that one of these days a driver release will resolve the issue, but until then...

Anonymous said...

Very interesting, we were having a problem on our 2950 cluster running exchange failing over repeatedly until we disabled chimney.

Stephen Flynn said...

I disabled chimney and everything started working. But then why even have that Broadcom nic if you can't do TCP offloading. I installed some Intel NICs and disabled the on board Broadcom and everything works much better now.

Steven Berkovitz said...

From what I understand, the issue is that the TOE engine only works up to a certain amount of connections (I don't remember the exact value, but it isn't very large). If you have connections under this amount, everything works fine, but the connections above and beyond this value will be dog slow.

Essentially the feature is useless except for very specific circumstances.

Regarding your question about why they even offer it, I don't know.

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Heri said...

I had the exact same problem with ISA2006, Dell and Broadcom. It just doesn't work. - In the end I decided to use the Dell/Broadcom server to something else - and installed ISA2006 on a Dell/Intel server.
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John Bond said...
This comment has been removed by the author.
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