Load spikes when new email arrives

[francis picabia]

On Thu, Jan 24, 2013 at 2:06 PM, Wesley Craig <wescraig at columbia.edu> wrote:

> You might find this helpful:
>
>         http://lwn.net/Articles/328363/
>
> regarding fsync (lmtpd) latency on Linux.  Lowering the lmtpd process
> limit ought to fix your load problem, but you should be aware how cyrus
> master implements that limit: your postfix processes will still make
> connections, but they will appear to hang when you're at the limit.  This
> will transform your spike to a hill, but you may end up with lots of
> waiting postfix processes.
>
>
Responding to the list where I'd like to hear more feedback on this.

We are running ext3 but could easily convert it to ext4.  Has anyone
experienced that upgrade on their cyrus mail partitions?  Does it
improve latency enough to make a significant difference when IO is
saturated?

I have reduced the lmtpd max to 5.  Now the load maxes at about 10.
It does take longer to work through the queue, but it eventually
settles down (e.g. 10 minutes instead of 3 or 4)
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