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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Understood. Thanks for all your help, Sunil. Looks like this just isn’t a good fit for my environment.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>-Nick<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> Sunil Mushran [mailto:sunil.mushran@oracle.com] <br><b>Sent:</b> Friday, August 19, 2011 3:54 PM<br><b>To:</b> Nick Geron<br><b>Cc:</b> ocfs2-users@oss.oracle.com<br><b>Subject:</b> Re: [Ocfs2-users] IO performance appears slow<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The cluster stack uses the interconnect to negotiate the locks.<br>That's how it is able to provide data coherency. Other solutions<br>do not provide that kind of coherency.<br><br>If you are referring to interconnect speeds in ms, it is not good.<br>That unit is typically used for disk access.<br><br>On 08/19/2011 01:30 PM, Nick Geron wrote: <o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'>Actually those first numbers were from GigE links going out to physical switches and back in. To optimize the private link, I upgraded the VMs NICs to 10GE (VMXNet3 which is the VMware para virt driver), moved them onto the same host system with a dedicated software switch between them. The numbers only improved slightly, and got worse on 1 of 100 pings (1ms). </span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'>10GE between VMs under the same hypervisor: rtt min/avg/max/mdev = 0.194/0.307/1.003/0.132 ms</span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'>What I don’t understand is why my OCFS2 cluster suffers so greatly. There’s quite a big difference between wall time of 0.17 seconds to traverse the data on an iSCSI link and the 4 minutes to do the same on OCFS2 with a sub 1ms average latent private interconnect. For that matter, the whole setup is running on another clustered FS (VMFS3) over the same network to the same SAN. I guess I’m just a little dumbfounded that OCFS2 is so much more demanding than other clustered FSs and alternative network storage options.</span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'>Is the network really the most likely candidate? If so, is anyone else running OCFS2 from within a VM environment? Is this technology only worthwhile in the physical world? Is there a sweet spot for network latency that I should strive for? The user guide only makes mention of ‘low latency’ but lacks figures save for heartbeat and timeouts.</span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'>-nick</span><o:p></o:p></p></div></body></html>