[dm-devel] performance considerations with IO schedulers and DMmultipathing

[Romanowski, John (OFT)]

Here's some links:

Google cache of this article:
"The basis for my test was to determine the best possible performance combination of elevator tuning AND /etc/multipath.conf rr_min_io setting."
http://72.14.209.104/search?q=cache:q2p5HOwGxHwJ:www.techyblog.com/content/view/45/28/+Multipath+rr_min_io+Oracle+Elevator+Benchmarks&hl=en&ct=clnk&cd=1&gl=us

"The short summary of our study indicates that there is no SINGLE answer to which I/O scheduler is best."
http://www.redhat.com/magazine/008jun05/features/schedulers/

Oracle and linux I/O Scheduler
part 1- http://www.nextre.it/oracledocs/ioscheduler_01.html
part 2- http://www.nextre.it/oracledocs/ioscheduler_02.html
part 3- http://www.nextre.it/oracledocs/ioscheduler_03.html


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-----Original Message-----

From: dm-devel-bounces at redhat.com on behalf of Stefan Bader
Sent: Tue 11/27/2007 4:42 PM
To: device-mapper development
Subject: Re: [dm-devel] performance considerations with IO schedulers and DMmultipathing
 
Hi Paul,

the device-mapper target itself doe not use any queue and so there is no
scheduler used at all. Only the real devices that are used as paths will be
using a scheduler. Whether there might be a performance gain by changing
these, I do not know.

Stefan

2007/11/27, Paul Cote <paul.cote at incipient.com>:
>
>  Hi,
>
> Is there any advantage to one specific IO scheduler (below) that may
> improve IO performance / throughput when running with a round-robin failover
> policy? Has anyone done testing with this ... and willing to share results?
>
> thanks,
> Paul
>
> Completely Fair Queuing-elevator=cfq (default)
> Deadline-elevator=deadline
> NOOP-elevator=noop
> Anticipatory-elevator=as
>
>
>
> --
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>