From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: striping of a 4 drive raid10 Date: Sun, 27 Jan 2008 20:33:45 +0100 Message-ID: <20080127193345.GA5426@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi I have tried to make a striping raid out of my new 4 x 1 TB SATA-2 disks. I tried raid10,f2 in several ways: 1: md0 = raid10,f2 of sda1+sdb1, md1= raid10,f2 of sdc1+sdd1, md2 = raid0 of md0+md1 2: md0 = raid0 of sda1+sdb1, md1= raid0 of sdc1+sdd1, md2 = raid01,f2 of md0+md1 3: md0 = raid10,f2 of sda1+sdb1, md1= raid10,f2 of sdc1+sdd1, chunksize of md0 =md1 =128 KB, md2 = raid0 of md0+md1 chunksize = 256 KB 4: md0 = raid0 of sda1+sdb1, md1= raid0 of sdc1+sdd1, chunksize of md0 = md1 = 128 KB, md2 = raid01,f2 of md0+md1 chunksize = 256 KB 5: md0= raid10,f4 of sda1+sdb1+sdc1+sdd1 My new disks give a transfer rate of about 80 MB/s, so I expected to have something like 320 MB/s for the whole raid, but I did not get more than about 180 MB/s. I think it may be something with the layout, that in effect the drives should be something like: sda1 sdb1 sdc1 sdd1 0 1 2 3 4 5 6 7 And this was not really doable for the combination of raids, because thet combinations give different block layouts. How can it be done? Do we need a new raid type? Best regards keld