On Tue, Oct 19, 2010 at 1:35 PM, Ravi Kanth <span dir="ltr"><<a href="mailto:raveeknth@gmail.com">raveeknth@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<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>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/">http://lwn.net/Articles/292984/</a></div>
<div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<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>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><div>-JR</div></div>