Re: Replication speeds?

[Wesley Craig]

Obviously looking at more iostat information would give a better idea, but I'd estimate that you are NOT I/O bound. Sorry I can't give you absolute numbers from UM, but I can share a patch that we wrote that we believe has increase sync throughput substantially, as evidenced by the lack of a sync backlog which we were getting before we added the patch.

        http://en.wikipedia.org/wiki/Nagle's_algorithm



:wes

The patch itself is pretty simple. As with most TCP-based request- response protocols, the Cyrus sync protocol suffers from artificial "Nagle" delays. See: for what's good about Nagle's algorithm. The patch disables Nagle delays in both sync_client and sync_server.

nodelay.diff
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On 09 May 2007, at 11:05, Nik Conwell wrote:

What sort of rates are you all getting for replication?



Is this speed typical or abysmal?

Disks appear to be holding me back:



Production (40,000+ users) would probably be FC and gigE...

At 2.3.7 for a manual sync_client for a user, I'm seeing ~35MB/ minute across a 100M net to a linux SW RAID 1 pair of U320 disks. Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util dm-0 0.00 0.00 0.00 429.96 0.00 3439.65 0.00 1719.83 8.00 7.24 16.75 1.86 80.01

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