<div>My machines have 4 processors (Intel Xeon CPU E5430 @ 2.66 Ghz) on each machine, 4GB RAM and 2.6.18-194.11.4.el5 linux kernel version. </div>
<div> </div>
<div>Problem I was trying to solve was syning the data between 3 machines. Consider we have 3 machined A, B, C. If you sync A-B then disconnect them and connect B-C then they are synced for the first time. Now If we disconnect B-C and reconnect A-B and write some data onto the disks, these data changes are not getting recognised or found when we connect B-C. So when I do a drbdadm verify I can find the out-of-sync blocks. But this process seems to be very slow (60Mbps). Is there any other way to find out of sync blocks on the disks?</div>
<div> </div>
<div>Is there any way I could (i mean drbd) write to metadata, changes that are being made even when the disks are connected as primary/secondary?</div>
<div> </div>
<div>If I have 4 processors, will they be all used? Or should I make any changes to use all of them? Does increasing RAM might have any <br>increase in performance? </div>
<div> </div>
<div>Ravee<br></div>
<div class="gmail_quote">On Tue, Oct 19, 2010 at 9:26 PM, J. Ryan Earl <span dir="ltr"><<a href="mailto:oss@jryanearl.us" target="_blank">oss@jryanearl.us</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote">
<div>On Tue, Oct 19, 2010 at 1:35 PM, Ravi Kanth <span dir="ltr"><<a href="mailto:raveeknth@gmail.com" target="_blank">raveeknth@gmail.com</a>></span> wrote:<br></div>
<div class="gmail_quote">
<div>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote">
<div>I am trying to use drbdadm verify resources and I can only get 60Mbps data rate. I am using infiniband and my syncer rate is 500Mbps.</div></blockquote>
<div><br></div></div>
<div>InfiniBand doesn't matter, you'd get the same verification performance on a GigE network as you are CPU limited; single-thread limited to be precise. You need a faster CPU or a dedicated checksum engine such as the CRC32C implementation in the newer 32nm Intel processors with a sufficiently new revision of the kernel: <a href="http://lwn.net/Articles/292984/" target="_blank">http://lwn.net/Articles/292984/</a></div>
<div>
<div><br></div>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex" class="gmail_quote">
<div>Is there any setting that I can change for the verification to happen at the full bandwidth speed? I want to use the full bandwidth for verification.</div></blockquote>
<div><br></div></div>
<div>You can try different checksum algorithms. The bandwidth used by the checksum verify is a small fraction of the reported checksumming speed. Unfortunately the verify requires a checksumming algorithm at the moment, in your case where bandwidth between hosts is gratuitous, it would be more efficient to NOT calculate checksums at all and just compare raw data. To my knowledge, DRBD does not support this currently.</div>
<div><br></div><font color="#888888">
<div>-JR</div></font></div></blockquote></div><br>