<div dir="ltr">Well, if you want to join my tests, here are a couple of sysctl options:<div><br></div><div><div>net.core.wmem_max=12582912</div><div>net.core.rmem_max=12582912</div><div>net.ipv4.tcp_rmem= 10240 87380 12582912</div>
<div>net.ipv4.tcp_wmem= 10240 87380 12582912</div><div>net.ipv4.tcp_window_scaling = 1</div><div>net.ipv4.tcp_timestamps = 1</div><div>net.ipv4.tcp_sack = 1</div><div>vm.swappiness=10</div><div>vm.dirty_background_ratio=1</div>
<div>net.ipv4.neigh.default.gc_thresh2=2048</div><div>net.ipv4.neigh.default.gc_thresh3=4096</div><div>net.core.netdev_max_backlog=2500</div><div>net.ipv4.tcp_mem= 12582912 12582912 12582912</div></div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Fri, Mar 21, 2014 at 12:05 AM, Josh Boon <span dir="ltr"><<a href="mailto:gluster@joshboon.com" target="_blank">gluster@joshboon.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div style="font-size:10pt;font-family:Arial"><div>Hey folks,</div><div><br></div><div>We've been running VM's on qemu using a replicated gluster volume connecting using gfapi and things have been going well for the most part. Something we've noticed though is that we have problems with many concurrent disk operations and disk latency. The latency gets bad enough that the process eats the cpu and the entire machine stalls. The place where we've seen it the worst is a apache2 server under very high load which had to be converted to raw disk image due to performance issues. The hypervisors are connected directly to each other over a bonded pair of 10Gb fiber modules and are the only bricks in the volume. Volume info is </div>
<div><br></div><div><p style="margin:0px">Volume Name: VMARRAY<br>Type: Replicate<br>Volume ID: 67b3ad79-4b48-4597-9433-47063f90a7a0<br>Status: Started<br>Number of Bricks: 1 x 2 = 2<br>Transport-type: tcp<br>Bricks:<br>Brick1: 10.9.1.1:/mnt/xfs/VMARRAY<br>
Brick2: 10.9.1.2:/mnt/xfs/VMARRAY<br>Options Reconfigured:<br>nfs.disable: on<br>network.ping-timeout: 7<br>cluster.eager-lock: on<br>performance.flush-behind: on<br>performance.write-behind: on<br>performance.write-behind-window-size: 4MB<br>
performance.cache-size: 1GB<br>server.allow-insecure: on<br>diagnostics.client-log-level: ERROR</p><p style="margin:0px"><br></p><p style="margin:0px">Any advice for performance improvements for high IO / low bandwidth tuning would be appreciated. </p>
<p style="margin:0px"><br></p><p style="margin:0px">Thanks,</p><p style="margin:0px">Josh</p></div></div></div><br>_______________________________________________<br>
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