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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have setup two Vmware virtual machines to replicate their storage with DRBD using protocol C. So far the write performance isn’t as good as I had hoped.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have tested write performance using fio and right now the best I can get is write throughput and IOPS that are about 50-75% as good as with drbd replication disabled. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My setup is two identical Centos 5.5 VMs running drbd 8.3.8. The link between them is two dedicated 10Gb adapters, no switch in between. I feel the link is not the bottleneck but something in my drbd config.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have followed the tuning recommendations on the linbit site and have seen some small improvements, but still don’t have the performance I was hoping for. I thought I would be able to get a write penalty more like 10%, not the 25-50% I am seeing. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I added no-disk-flushes; and no-md-flushes;. <o:p></o:p></p><p class=MsoNormal>I set max buffers and max-epoch-size to 8196, and also experimented with several unplug-watermark sizes.<o:p></o:p></p><p class=MsoNormal>I also set my hardware RAID controller to 100% write cache. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> I attached my drbd.conf. Any other ideas would be most appreciated. Thank you<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sean<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>