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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal">I have a real sticky problem and would appreciate if anyone has insight.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We currently have the following physical configuration<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2) Dell PowerEdge R710 (dual 6-core with hyperthreading enabled)<o:p></o:p></p>
<p class="MsoNormal"> 120Gbytes of memory each<o:p></o:p></p>
<p class="MsoNormal"> 4x 10GE Nics (2-bonded for NFS and 2-bonded for Replication)
<span style="color:#1F497D"> Broadcom 57711.</span><o:p></o:p></p>
<p class="MsoNormal"> 4x 8Gbit FC HBAs which are tied to a dual controller NEXSAN E60 array (controllers in non-redundant mode), each controller has 4Gbytes of memory.<o:p></o:p></p>
<p class="MsoNormal"> Raw throughput is around 340Mbytes/sec per volume. <o:p>
</o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> Each system is running RHEL 6.3 with heartbeat and now with DRBD-8.4.2, problem was there with 8.4.0 (could not get 8.4.1 to work).<o:p></o:p></p>
<p class="MsoNormal">System configured as Active/Passive pair with EXT4 and the filesystem, barriers off. Filesystems exported via NFS to vSphere 4.1 clients.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> Main problem is that everything works for most of the time but every now and then a resource stall (high load average and no I/O) occurs which<o:p></o:p></p>
<p class="MsoNormal">Is not good for running VMs. Has anyone seen this? No errors recorded just no I/O and high load for a few minutes (3-4). This has been driving<o:p></o:p></p>
<p class="MsoNormal">me crazy. One more thing, these events do not occur with “replication disabled” i.e. drbdadm down all (on the peer member).
<span style="color:#1F497D"> I have adjusted<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">many sysctl parameters (up memory buffers , etc) , changed I/O schedulers and turned on and off hyperthreading and still have the issue.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks in advance.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">James<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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