On Tue, 13 Dec 2011, Joshua Baker-LePain wrote:

> On Wed, 14 Dec 2011 at 12:20pm, SINCOCK John wrote
>
>> Any advice on what might be going on here would be appreciated! - should
>> it really be necessary to delve into tuning vm system parameters just to
>> avoid memory fragmentation causing device drivers and system calls to
>> fail? To be messing around trying different vm paramaters just to make a
>> machine usable doesn't seem to make sense.
>
> What I/O scheduler are you using?  I've seen some suggest that when using a 
> (real) RAID card, the deadline scheduler is preferred over the default cfq. 
> Also, what FS are you using for your holding area?  Finally, what is the 
> nature of the data you're backing up (i.e. does it involve *lots* of small 
> files)?

BTW, there was an interesting presentation at LinuxCon in Vancouver this past
summer by Christoph Hellwig on Filesystem/Storage tuning:

  https://events.linuxfoundation.org/slides/2011/linuxcon/lcna2011_hellwig.pdf

In it he says the the default cfg I/O scheduler is a very bad default,
except on single-SATA spindle desktops - he recommends the deadline
scheduler.

cheers, etc.
-- 
deatrich @ triumf.ca, Science/Atlas         PH: +1 604-222-7665
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