From: Sebastian Riemer <sebastian.riemer@profitbricks.com>
To: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Cc: Roberto Spadim <roberto@spadim.com.br>,
Linux RAID Mailing List <linux-raid@vger.kernel.org>
Subject: Re: Reason for md raid1 max_sectors_kb limited to 127?
Date: Mon, 07 May 2012 17:33:40 +0200 [thread overview]
Message-ID: <4FA7EB54.60305@profitbricks.com> (raw)
In-Reply-To: <4FA7E095.7080909@itwm.fraunhofer.de>
On 07/05/12 16:47, Bernd Schubert wrote:
> On 05/07/2012 04:44 PM, Roberto Spadim wrote:
>> could check if it have any performace increase? maybe i consider
>> upgrading my kernel to get more performace inn raid1
>>
>
> Depends on your hardware. Hardware that can handle small IO sizes, such
> as common hard disks usually don't have problems with 512KB IOs. But if
> you should use software on top of hardware raid large IOs might be very
> important (again depends on the hw-raid vendor then).
>
>
> Cheers,
> Bernd
O.K., I've also tested 3.2.16 and there the problem still exists.
Bernd pinpointed me to commit b1bd055d397e09f99dcef9b138ed104ff1812fcb
(block: Introduce blk_set_stacking_limits function).
After cherry-picking it on 3.2.16 it worked. Tomorrow I'll test the
performance impact and verify it by block tracing.
Cheers,
Sebastian
next prev parent reply other threads:[~2012-05-07 15:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-07 9:41 Reason for md raid1 max_sectors_kb limited to 127? Sebastian Riemer
2012-05-07 11:18 ` NeilBrown
2012-05-07 11:34 ` Sebastian Riemer
2012-05-07 14:04 ` Bernd Schubert
2012-05-07 14:14 ` Sebastian Riemer
[not found] ` <CABYL=ToyVwRGOkVs63iBgfWeTsjDQ=ofsYC4hgAVpABrWbHUjA@mail.gmail.com>
2012-05-07 14:47 ` Bernd Schubert
2012-05-07 15:33 ` Sebastian Riemer [this message]
2012-05-07 16:13 ` Bernd Schubert
-- strict thread matches above, loose matches on Subject: below --
2012-05-08 16:07 Sebastian Riemer
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