From mboxrd@z Thu Jan 1 00:00:00 1970 From: adfas asd Subject: Re: Disappointing RAID10 Performance Date: Fri, 16 Oct 2009 14:05:56 -0700 (PDT) Message-ID: <715541.19877.qm@web38803.mail.mud.yahoo.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids --- On Fri, 10/16/09, Rob Becker wrote: > What command did you use to create your > raid-10? / mdadm --create /dev/md0 --level=raid1 --chunk=256 --raid-disks=2 missing /dev/sdb1 swap mdadm --create /dev/md1 --level=raid10 --layout=o2 --chunk=256 --raid-disks=2 missing /dev/sdb2 /home mdadm --create /dev/md2 --level=raid10 --layout=o2 --chunk=1024 --raid-disks=2 missing /dev/sdb3 ... then copied files and later added the sda parts to the array. (RAID conversion on live system) > You might try > running iostat in parallel to see if the read_balancer is > properly > balancing the reads between the two disks. Don't understand this as I'm a bit of a n00b... --- On Fri, 10/16/09, Tomasz Chmielewski wrote: > If you only use your RAID-10 array for a single "dd > if=bigfile of=/dev/null" then yes, it does not give you much > over mirroring. > > If you start using your drives for two "dd if=bigfile[12] > of=/dev/null" at the same time, you will notice the > difference. OK so it was a fallacy to think this would help with large files, unless more than one is involved.