Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
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. 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? 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? 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 increase in performance? Ravee On Tue, Oct 19, 2010 at 9:26 PM, J. Ryan Earl <oss at jryanearl.us> wrote: > On Tue, Oct 19, 2010 at 1:35 PM, Ravi Kanth <raveeknth at gmail.com> wrote: > >> 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. >> > > 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: http://lwn.net/Articles/292984/ > > 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. >> > > 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. > > -JR > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20101021/b5cd31b0/attachment.htm>