On 3/18/2016 2:39 PM, Jim Lohiser wrote:
> David,
>
> Is all of SurgeMail on the same partition in Linux?
the code is in the / partition and the mailstore is in a different one.
we've been running like that since the dmail days.
> Do you have any users with 10s of thousands of emails in one folder?
well, i actually discovered one today. in fact, there may be more, but
why would that cause huge amounts of write activity?
> Jim Lohiser
> N2Net
>
> -----Original Message-----
> From: David Camm [mailtoHIDDEN@advwebsys.com]
> Sent: Friday, March 18, 2016 3:37 PM
> To: SurgeMail List
> Subject: [SurgeMail List] huge io spikes lead to huge load average
>
> we're running on a 4-core, 4G, raid5 machine running open suse linux.
>
> the kernel thinks we have 8 cores.
>
> under most circumstances, surgemail just hums along with a load average
> anywhere from .5 to 4, which is just fine.
>
> several times lately, we've seen the load average spike to 10 or more
> and remain there for several minutes, at which point i stop surgemail,
> wait a bit and restart.
>
> what we've determined is that there's a HUGE amount of io activity
> occurring when this happens and the system becomes io-bound.
>
> we've tried running iotop, but that only tells us surgemail is writing a
> gazillion kb per second. not very helpful. examining the logs hasn't
> proved to be useful either.
>
> so.......
>
> is there any diagnostic we can run to determine what's happening and why
> there's such a huge io load?
>
> and, can anyone give some insight as to what situation might cause this
> to happen in the first place?
>
> btw - we're very conservative and limit email size to 20MB, so it can't
> be someone trying to receive a file with a 1GB attachment. it also
> can't be hackers attempting to log in, as that would just generate small
> writes to mail.err.
>
> david camm
> advanced web systems
> keller, tx
>
>
>
>
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