From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raz Ben Jehuda Subject: Re: RAID5 question. Date: Thu, 04 Aug 2005 18:56:58 +0300 Message-ID: <1123171018.9269.1.camel@localhost.localdomain> References: <17137.43778.476908.961140@cse.unsw.edu.au> <01f001c598fd$c59a51a0$0400a8c0@LocalHost> <1123164866.8854.0.camel@localhost.localdomain> <42F22C8F.4000407@dgreaves.com> <025301c5990b$8b456cc0$0400a8c0@LocalHost> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <025301c5990b$8b456cc0$0400a8c0@LocalHost> Sender: linux-raid-owner@vger.kernel.org To: djani22@dynamicweb.hu Cc: David Greaves , linux-raid@vger.kernel.org List-Id: linux-raid.ids 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" > To: "Raz Ben Jehuda" > Cc: ; > 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 > > >> > > >> > > > > > > -- > > > > - > > 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 > > - > 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 -- Raz Long live the penguin