[DRBD-user] suffering from iowait

Tom Hayman Tom.Hayman at Markettiers4DC.com
Fri Aug 15 13:31:51 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

* Mark Watts <m.watts at eris.qinetiq.com> [2008-08-15 11:47]:
> On Friday 15 August 2008 10:19:22 Wolfram Schlich wrote:
> > * Mark Watts <m.watts at eris.qinetiq.com> [2008-08-15 10:56]:
> > > [...]
> > > Similar IO problems have been reported before (search the archives
> > > TOE) and its been found that even if TCP Offload isn't enabled by
the nic
> > > driver, the hardware key seems to enable it.
> > >
> > > If you pop the lid on the server, you should find (if you server
has TOE)
> > > a little RJ11 dongle you can remove to fully disable TOE.
> > >
> > > I've done this on some 1950's and it solved my IO problems.
> >
> > Hmm: http://tinyurl.com/5nehl6 (a long dell.com URL)
> > --8<--
> > To disable the TCP Offloading Engine (TOE) capability of Broadcom
> > adapters, TOE must be turned off in Broadcom advanced controller
> > (BACS) or at the command line. Removing the TOE key causes
> > failures because it is not the valid method of disabling TOE.
> > --8<--
> > Maybe it's only a problem under Windows ;)
> Well, I (and probably others) have removed those keys with nothing but

> positive effects.
>Good to know!
> > Also, the PE860 has a BCM5721 NIC, which does not seem to support
> Ah well. Worth a shot.

Our two HP RHE 5 servers are suffering from high IOWait, and it's
currently so bad we are thinking of moving away from DRBD altogether.
When problems occur the CPU's jump to 100 and we are getting kernel
panics.  We use Broadcom NetXtreme2 NICs for our DRBD set up - TX & RX
checksumming offload are enabled on each NIC.  I'm thinking of doing the
following to disable this:

ethtool -K eth0 rx off
ethtool -K eth0 tx off
ethtool -K eth0 sg off
ethtool -K eth1 rx off
ethtool -K eth1 tx off
ethtool -K eth1 sg off_

Will this make a difference?



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