From: Wesley Craig (no email)
Date: Wed May 09 2007 - 14:01:39 EDT
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.
The patch itself is pretty simple. As with most TCP-based request-
response protocols, the Cyrus sync protocol suffers from artificial
"Nagle" delays. See:
http://en.wikipedia.org/wiki/Nagle's_algorithm
for what's good about Nagle's algorithm. The patch disables Nagle
delays in both sync_client and sync_server.
:wes
On 09 May 2007, at 11:05, Nik Conwell wrote:
> What sort of rates are you all getting for replication?
>
> 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.
>
> Is this speed typical or abysmal?
>
> Disks appear to be holding me back:
>
> 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
>
> Production (40,000+ users) would probably be FC and gigE...
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