Re: RAID5 question.

[djani22@dynamicweb.hu]

Yes, it is there, I know it.
But its only for resync or not? :-)

----- Original Message -----
From: "Raz Ben Jehuda" <razb@bitband.com>
To: <djani22@dynamicweb.hu>
Cc: "David Greaves" <david@dgreaves.com>; <linux-raid@vger.kernel.org>
Sent: Thursday, August 04, 2005 5:56 PM
Subject: Re: RAID5 question.


> take a look at /proc/sys/dev/raid/speed_limit_max . it is kilobytes if i
> recall correctly.
>
> On Thu, 2005-08-04 at 17:45 +0200, djani22@dynamicweb.hu wrote:
> > Thanks a lot for you, and Raz!
> >
> > The raw devices readahead I already set with the hdparm, and
> > /sys/block/*/queue/read_ahead_kb, but the md device is only changeable
with
> > blockdev. :-)
> > I dont use lvm, because it is too slow for me....
> >
> > But unfortunately the problem is still here for me. :(
> > I continue searching the bottleneck...
> >
> > Thanks!
> >
> > Janos
> >
> > ----- Original Message -----
> > From: "David Greaves" <david@dgreaves.com>
> > To: "Raz Ben Jehuda" <razb@bitband.com>
> > Cc: <djani22@dynamicweb.hu>; <linux-raid@vger.kernel.org>
> > Sent: Thursday, August 04, 2005 4:56 PM
> > Subject: Re: RAID5 question.
> >
> >
> > > And notice you can apply different readahead to:
> > > The raw devices (/dev/sda)
> > > The md device (/dev/mdX)
> > > Any lvm device (/dev/lvm_name/lvm_device)
> > >
> > > David
> > >
> > > Raz Ben Jehuda wrote:
> > >
> > > >read the blockdev man page
> > > >
> > > >On Thu, 2005-08-04 at 16:06 +0200, djani22@dynamicweb.hu wrote:
> > > >
> > > >
> > > >>Hi list, Neil!
> > > >>
> > > >>I have a little question because I'v got some performance problem...
> > > >>Is the RAID5 do any type of headahead with the default config?
> > > >>It is possible to disable the readahead? (if it is.)
> > > >>Or just the io_sched do that on the disks?
> > > >>
> > > >>How can I disable the whole headahead on top of the RAID5 array?
> > > >>
> > > >>The RAID5 can do multiple small (<4kb) reads of disks for the
> > multithreaded
> > > >>read requests?
> > > >>(chunk size is 32k)
> > > >>
> > > >>Thanks for helping!
> > > >>
> > > >>Janos
> > > >>
> > > >>-
> > > >>To unsubscribe from this list: send the line "unsubscribe
linux-raid" in
> > > >>the body of a message to majordomo@vger.kernel.org
> > > >>More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > >>
> > > >>
> > >
> > >
> > > --
> > >
> > > -
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> >
> > -
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> --
> Raz
> Long live the penguin
>
> -
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