From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Rabbitson Subject: Raid1 replaced with raid10? Date: Tue, 20 Mar 2007 00:25:19 +0100 Message-ID: <45FF1BDF.6060304@rabbit.us> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi, I just tried an idea I got after fiddling with raid10 and to my dismay it worked as I thought it will. I used two small partitions on separate disks to create a raid1 array. Then I did dd if=/dev/md2 of=/dev/null. I got only one of the disks reading. Nothing unexpected. Then I created a raid10 array on the same two partitions with the options -l10 -n2 -pf2. The same dd executed at twice the speed, reading _simultaneously_ from both drives. I did some bonnie++ benchmarking - same result - raid1 reads only from a single disk raid10 from both. Write performance is worse (about 10% slower) with raid10, but you get twice the read speed. In this light the obvious question is: can raid10 be used as a drop-in replacement for raid1 or there is a caveat with having the amount of disks equal the amount of chunk copies? Peter