From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: Why are reads not balanced across my RAID-1? Date: Thu, 30 Jan 2014 15:05:10 -0500 Message-ID: <52EAB076.8070301@ubuntu.com> References: <20140125011832.23432.qmail@science.horizon.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140125011832.23432.qmail@science.horizon.com> Sender: linux-raid-owner@vger.kernel.org To: George Spelvin , keld@keldix.com, rspadim@gmail.com Cc: linux-raid@vger.kernel.org, matthew.garman@gmail.com List-Id: linux-raid.ids -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 1/24/2014 8:18 PM, George Spelvin wrote: > Obviously, if I added disks and striped across them, sequential > performance would go up. This is an actual RAID-10 layout. But > it's not useful unless I buy more disks. No, md can do raid10 on two disks, just not in the near layout. The offset layout with a sufficiently large chunk size mostly does what you want. I recently set myself up with a 3 disk array like that and it pushes 500 MB/s using cheap, run of the mill 1 TB WD Blue drives. The offset layout gives slightly better performance than far ( as long as you use a sufficiently large chunk size ), and can be resized, unlike far. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJS6rB2AAoJEI5FoCIzSKrwCgUH/2ObIJbpgipuSpf1JsTLyMJk zJnRkKISS6/1MiEtiBLRDYHhi2yL/B0S/J5jRSmgeLbAuM/q1cfF7BSOKfP52qUS frDIRO0AtWybE/8NNiLMe6dBG1Zkfn/P+atMQwGGfy5wMWAU1DcCzq/qlv+dVkP7 VHaGuEKm/A1ySzwxnKdPTbAfe1/wRrBDeQg4leZRP9nBLA+jDWmw3oGlHW/7Aeeb DCKKzU6+V1Hqrk8kmayh6A6D5Dp8AdPoMEj7q/I8edNX/Zp8NI/yH2wOrEkXI/xK kiE2E0kRHyTFQ2VxU0rGKzYzE4fcjtoaDdQxHhc58/5LkUE3PTDsTyBxKn0XsHU= =G5bT -----END PGP SIGNATURE-----