[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] high I/O cost for drbd and xen?
> Just run some benchmarks on my new failover cluster and found some > alarming results. I've previously observed that xen typically > introduces > almost zero IO overhead. I ran some tests with bonnie -x 10 on my drbd > mirrors and compared the averages between dom0 and dom1 to see the > virtualisation cost. I was surprised (and alarmed) to see > that there was > a fairly high cost for read operations (high being >10%). I was very > concerned to see the 80% cost for get_block on the failover node. Not sure what's going on here as I've never used drbd. I'd be inclined to run drbd in domain 0 and export the device to the guest rather than run drbd in the guest. Ian > Could this be a scheduler issue? drbd likes to be high > priority - it's a > high availability service after all. Perhaps the hypervisor > is blocking > it > or not allowing it its normal share of cpu time? Perhaps its > giving CPU > time from drbd on dom0 to bonnie on dom1, causing the > reported slowdown? > > Tom > > > ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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