From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Robinson Subject: Re: standard performance (write speed 20Mb/s) Date: Wed, 27 Jul 2011 11:26:39 +0100 Message-ID: <4E2FE7DF.1020906@anonymous.org.uk> References: <201107162140.58883.raid1@fuckaround.org> <4E226464.2030200@hardwarefreak.com> <4E22D167.2010905@anonymous.org.uk> <4E2FE6C9.4070604@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4E2FE6C9.4070604@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: Stan Hoeppner Cc: Simon Matthews , Pol Hallen , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 27/07/2011 11:22, Stan Hoeppner wrote: > On 7/27/2011 12:42 AM, Simon Matthews wrote: >> On Sun, Jul 17, 2011 at 5:11 AM, John Robinson >> wrote: >> >>> Pretty poor. CentOS 5, Intel ICH10, md RAID 6 over 5 7200rpm 1TB drives, >>> then LVM, then ext3: >>> # dd if=/dev/zero of=test bs=4096 count=262144 >>> 262144+0 records in >>> 262144+0 records out >>> 1073741824 bytes (1.1 GB) copied, 2.5253 seconds, 425 MB/s >> >> What hard drive offers a sustained data rate of 425 MB/s or even half that? > > 425 MB/s / 3 spindles = 142 MB/s per spindle > > That's not poor, it's excellent. Which drives are these? WD Black, > Seagate, Hitachi? Gentlemen, we've been round this loop before about 10 days ago. Pol's 20 MB/s was poor because he was testing on an array with unaligned partitions and a resync was running, my 425 MB/s was a bad test because it didn't use fdatasync or direct and I said dd was a bad test anyway, etc etc. Cheers, John.