[Dovecot] IO rate quotas?

Eric Shubert ejs at shubes.net
Mon Apr 11 21:14:55 EEST 2011

On 04/11/2011 03:58 AM, Alan Brown 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.

This is what I suspected, but failed to verify.

I really need to look into TBird's latest settings.

> 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

Thanks for your insights, Alan.

-Eric 'shubes'

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