On 07/02/13 18:02, Carsten Aulbert wrote:
> Hi Adam
>
> On 02/07/2013 07:48 AM, Adam Goryachev wrote:
>>
>> Each drive only has a single partition, and is partitioned a little
>> smaller than the drive (supposedly this should improve performance).
>> Each drive is set to the deadline scheduler.
>
> First, I'd start with the deadline scheduler.
Already using it, am going to try noop shortly....
> Even for rotating rust systems you can improve performance quite a bit,
> but with SSDs you might hit the limits way too early and need to tune it.
>
> Save the current default values somewhere safe, so you can go back
> easily, then start tuning these values (as a start):
>
> for i in $(grep \^md /proc/mdstat |cut -d' ' -f 5-); do
> DEV=${i:0:3}
> echo deadline > /sys/block/$DEV/queue/scheduler
> echo 4096 > /sys/block/$DEV/queue/nr_requests
> echo 8192 > /sys/block/$DEV/queue/read_ahead_kb
> echo 5000 > /sys/block/$DEV/queue/iosched/read_expire
> echo 1000 > /sys/block/$DEV/queue/iosched/write_expire
> echo 2048 > /sys/block/$DEV/queue/iosched/fifo_batch
> done
>
> At least setting these helped quite a bit.
Do you have any information on what your workload is, or how/why these
values might help?
You are changing values significantly from the default, and I am
cautious that they may cause other issues. Also, someone else has
advised to reduce nr_requests rather than increasing it?
Thank you for your advice.
Regards,
Adam
--
Adam Goryachev
Website Managers
www.websitemanagers.com.au
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