<html><body bgcolor="#FFFFFF"><div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.296875); -webkit-composition-fill-color: rgba(175, 192, 227, 0.230469); -webkit-composition-frame-color: rgba(77, 128, 180, 0.230469); ">On Jul 27, 2009, at 4:09 PM, Coert Waagmeester <<a href="mailto:lgroups@waagmeester.co.za">lgroups@waagmeester.co.za</a>> wrote:</span><br></div></div><div><br></div><div></div><blockquote type="cite"><div><span></span><br><span>On Mon, 2009-07-27 at 12:37 +0200, Coert Waagmeester wrote:</span><br><blockquote type="cite"><span>On Mon, 2009-07-27 at 12:02 +0200, Alexander Dalloz wrote:</span><br></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><span></span><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><span>On Mon, 2009-07-27 at 08:30 +0200, Coert Waagmeester wrote:</span><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span></span><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><span>Hello Roman,</span><br></blockquote></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><span></span><br></blockquote></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><span>I am running drbd 8.2.6 (the standard centos version)</span><br></blockquote></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br><span></span></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span></span></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span>have you considered to test the drbd-8.3 packages?</span><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span></span><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span><a href="http://bugs.centos.org/view.php?id=3598">http://bugs.centos.org/view.php?id=3598</a></span><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span></span><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><span><a href="http://dev.centos.org/centos/5/testing/%7Bi386,x86_64%7D/RPMS/">http://dev.centos.org/centos/5/testing/{i386,x86_64}/RPMS/</a></span><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br><span></span></blockquote></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Thank you very much for this tip! It was one very obvious place where I</span><br></blockquote><blockquote type="cite"><span>did not look yet.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Would it be necessary to still recompile it for the TCP_NODELAY and</span><br></blockquote><blockquote type="cite"><span>such?</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>I am just making sure, because</span><br></blockquote><blockquote type="cite"><span><a href="http://www.nabble.com/Huge-latency-issue-with-8.2.6-td18947965.html">http://www.nabble.com/Huge-latency-issue-with-8.2.6-td18947965.html</a></span><br></blockquote><blockquote type="cite"><span>makes it seem unnecessary.</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>Why do the repositories provide both DRBD 8.0.x and 8.2.6?</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><span class="Apple-style-span" style="color: rgb(0, 80, 1);"><br></span><span>Here is a status update....</span><br><span>_______________________________________________________________________________</span><br><span>on both hosts I now run from the testing repository:</span><br><span># rpm -qa | grep drbd</span><br><span>drbd83-8.3.1-5.el5.centos</span><br><span>kmod-drbd83-xen-8.3.1-4.el5.centos</span><br><span>_______________________________________________________________________________</span><br><span>Here is my config (slightly condensed):</span><br><span>-----------------------------------------------------</span><br><span>global {</span><br><span> usage-count yes;</span><br><span>}</span><br><span>common {</span><br><span> protocol C;</span><br><span> syncer { rate 50M; }</span><br><span> net {</span><br><span># allow-two-primaries; }</span><br><span> sndbuf-size 0; }</span><br><span># disk {no-disk-flushes;</span><br><span># no-md-flushes; }</span><br><span> startup { wfc-timeout 0 ; }</span><br><span>}</span><br><span>resource xenfilesrv {</span><br><span> device /dev/drbd1;</span><br><span> disk /dev/vg0/xenfilesrv;</span><br><span> meta-disk internal;</span><br><span></span><br><span> on baldur.mydomain.local {</span><br><span> address 10.99.99.1:7788;</span><br><span> }</span><br><span> on thor.mydomain.local {</span><br><span> address 10.99.99.2:7788;</span><br><span> }</span><br><span>}</span><br><span>resource xenfilesrvdata {</span><br><span> device /dev/drbd2;</span><br><span> disk /dev/vg0/xenfilesrvdata;</span><br><span> meta-disk internal;</span><br><span></span><br><span> on baldur.mydomain.local {</span><br><span> address 10.99.99.1:7789;</span><br><span> }</span><br><span> on thor.mydomain.local {</span><br><span> address 10.99.99.2:7789;</span><br><span> }</span><br><span>}</span><br><span>_______________________________________________________________________________</span><br><span></span><br><span>xenfilesrv is a xen domU</span><br><span>in this domU i ran a dd with oflag direct:</span><br><span>---------------------------------------------------------</span><br><span># dd if=/dev/zero of=1gig.file bs=1M count=1000 oflag=direct</span><br><span>1000+0 records in</span><br><span>1000+0 records out</span><br><span>1048576000 bytes (1.0 GB) copied, 147.997 seconds, 7.1 MB/s</span><br><span></span><br><span>Just before I ran the dd this popped up in the secondary hosts syslog:</span><br><span>----------------------------------------------------------------------</span><br><span>Jul 27 21:51:42 thor kernel: drbd2: Method to ensure write ordering:</span><br><span>flush</span><br><span>Jul 27 21:51:42 thor kernel: drbd1: Method to ensure write ordering:</span><br><span>flush</span><br><span></span><br><span></span><br><span>_______________________________________________________________________________</span><br><span></span><br><span>What more can I try?</span><br><span></span><br><span>To be quite honest, I have no idea what to do with/ where to find the</span><br><span>TCP_NODELAY socket options......</span><br></div></blockquote><div><br></div>Use drbd option to disable flush/sync, but understand that during a power failure or system crash data will not be consistent on disk and you will need to sync the storage from the other server.<div><br></div><div>-Ross</div><div><br><div><br></div></div></body></html>