[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] high I/O cost for drbd and xen?
Hi all 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. 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 Attachment:
benchmarks.csv
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