On 2013-08-30 19:31, Stephen Marsh wrote: > Hi all, > > I've recently upgraded to DRBD 8.4.3 (protocol C) on CentOS 6.4 (kernel > 3.10.10) with Xen 4.3.0 on hardware RAID10 with an Infiniband 20Gbit/sec > replication link. > > For a few days now, we've been experiencing a very strange issue whereby > (seemingly randomly) the system will become almost unresponsive, with > iowait going to 100% on some (but not all) domUs and dom0, but even the > domUs whose load remains stable will still be incredibly sluggish. The > problem occurs even when the resources are in standalone mode.
One thing that I would check: if you are running the credit scheduler, dom0 may have run out of credits. Check/increase credit scheduler domain weights and make sure dom0 gets enough CPU time to serve i/o requests ... explained here in the Xen wiki http://goo.gl/fqtS6Y Regards, Andreas -- Need help with Linux-HA? http://www.hastexo.com/now > > Sometimes it self-corrects, but it's becoming more severe and is now > less likely to go away without a reboot. Earlier today, the system > running as primary was at 0.02 load, and the slave (which was doing > nothing other than receiving updates from the master, no domUs running) > went to 13 load and was pretty much dead. > > I've tried a variety of tuning options, including enabling > disable_sendpage, but nothing is making it any better. Nothing is > printed to the logs. > > My next thought is to try downgrading to DRBD 8.3, but considering > support ends in December, I'd much prefer to continue using 8.4. > > I'm very much hoping that someone more experienced than myself will be > able to offer some words of wisdom. :) > > Thanks > Regards, > Stephen Marsh > _______________________________________________ > drbd-user mailing list > [email protected] > http://lists.linbit.com/mailman/listinfo/drbd-user
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