Re: RAID5 question.

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how is the disks performance ? is it OK ?

On Thu, 2005-08-04 at 18:13 +0200, djani22@xxxxxxxxxxxxx wrote:
> Yes, it is there, I know it.
> But its only for resync or not? :-)
> 
> ----- Original Message -----
> From: "Raz Ben Jehuda" <razb@xxxxxxxxxxx>
> To: <djani22@xxxxxxxxxxxxx>
> Cc: "David Greaves" <david@xxxxxxxxxxxx>; <linux-raid@xxxxxxxxxxxxxxx>
> 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@xxxxxxxxxxxxx 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@xxxxxxxxxxxx>
> > > To: "Raz Ben Jehuda" <razb@xxxxxxxxxxx>
> > > Cc: <djani22@xxxxxxxxxxxxx>; <linux-raid@xxxxxxxxxxxxxxx>
> > > 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@xxxxxxxxxxxxx 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@xxxxxxxxxxxxxxx
> > > > >>More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > > >>
> > > > >>
> > > >
> > > >
> > > > --
> > > >
> > > > -
> > > > To unsubscribe from this list: send the line "unsubscribe linux-raid"
> in
> > > > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > >
> > > -
> > > To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> > > the body of a message to majordomo@xxxxxxxxxxxxxxx
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> > --
> > Raz
> > Long live the penguin
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
-- 
Raz
Long live the penguin

-
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