From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Greaves Subject: Re: RAID5 question. Date: Thu, 04 Aug 2005 15:56:15 +0100 Message-ID: <42F22C8F.4000407@dgreaves.com> References: <17137.43778.476908.961140@cse.unsw.edu.au> <01f001c598fd$c59a51a0$0400a8c0@LocalHost> <1123164866.8854.0.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1123164866.8854.0.camel@localhost.localdomain> Sender: linux-raid-owner@vger.kernel.org To: Raz Ben Jehuda Cc: djani22@dynamicweb.hu, linux-raid@vger.kernel.org List-Id: linux-raid.ids 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 >> >> --