From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.jrs-s.net ([173.230.137.22]:48798 "EHLO mail.jrs-s.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753802AbaBTQLH (ORCPT ); Thu, 20 Feb 2014 11:11:07 -0500 Received: from [192.168.100.50] (cpe-024-088-095-145.sc.res.rr.com [24.88.95.145]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: jim@jrs-s.net) by mail.jrs-s.net (Postfix) with ESMTPSA id 67A84D303 for ; Thu, 20 Feb 2014 11:11:05 -0500 (EST) Message-ID: <53062918.8090909@jrs-s.net> Date: Thu, 20 Feb 2014 11:11:04 -0500 From: Jim Salter MIME-Version: 1.0 To: linux-btrfs Subject: btrfs-raid10 - stripes or blocks? Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi list - Can anybody tell me whether btrfs-raid10 reads and writes a stripe at a time, like traditional raid10, or whether it reads and writes individual redundant blocks like btrfs-raid1, but just locks particular disks as mirror pairs, and/or locks the order in which mirror pairs should be written to in sequence? It occurs to me that this might be an important distinction for workloads with very high small random I/O - stripe reads and writes being at a disadvantage to individual blocks being read and written, when the requests are smaller than the stripe. Apologies again if this is a question that should have an obvious answer, but as long as it took me to figure out that btrfs-raid1 is NOT much like traditional raid1, it seemed worth asking.