[Dovecot] IO rate quotas?
Kádár Tamás (KTamas)
ktamas at ktamas.com
Mon Apr 11 20:20:47 EEST 2011
Wow, thanks everyone for the replies.
Already using XFS as a filesystem with noatime. Switching to faster
disks/raids/etc is not easy, we rent hosted server in Germany, to make
real changes i'd have to get my own server etc.
I'll play around with disk schedulers and report back.
Thanks again for all the help.
On Mon, Apr 11, 2011 at 12:58 PM, Alan Brown <ajb2 at mssl.ucl.ac.uk> wrote:
> From: Timo Sirainen <tss at iki.fi>
> Subject: Re: [Dovecot] IO rate quotas?
>> So a single process that is reading files fast enough from disk can
>> cause disk IO to spike in a way that makes all other processes wait for
>> available disk IO?
> It's not a single process.
> Thunderbird's newest defaults are to syncronize every folder and it will
> open one connectrion per folder in order to do that.
> Appropriate disk/swappiness/readahead/cache tuning is required - along with
> enough ram to cope with several users trying this at once.
> The underlaying filesystem is also important. as a for-instance, this kind
> of load with maildir format will effectively _kill_ a GFS box.
> Our fix was to install systemwide defaults on managed systems to not
> synchronize (not needed, the home directories are on network storage anyway)
> and to ask people to check/unset this on laptops/etc
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