From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: RE: RAID 6 grow problem Date: Wed, 6 Jun 2007 10:46:00 +1000 Message-ID: <18022.968.613733.320715@notabene.brown> References: <2076428235.1181071281354.JavaMail.root@gateway.korstad.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Jon Nelson on Tuesday June 5 Sender: linux-raid-owner@vger.kernel.org To: Jon Nelson Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tuesday June 5, jnelson-linux-raid@jamponi.net wrote: > > I have an EPoX 570SLI motherboard with 3 SATAII drives, all 320GiB: one > Hitachi, one Samsung, one Seagate. I built a RAID5 out of a partition > carved from each. I can issue a 'check' command and the rebuild speed > hovers around 70MB/s, sometimes up to 73MB/s, and dstat/iostat/whatever > confirms that each drive is sustaining approximately 70MB/s reads. > Therefore, 3x70MB/s = 210MB/s which is a bunch more than 133MB/s. lspci > -v reveals, for one of the interfaces (the others are pretty much the > same): ... > > I'm trying to determine what the limiting factor of my raid is: Is it > the drives, .... If look at the data sheets for the drives (I just had a look at a Seagate one, fairly easy to find on their web site) you should fine the Maximum Sustained Transfer Rate, which will be about 70MB/s for current 7200rpm drives. So I think the drive is the limiting factor. NeilBrown