From mboxrd@z Thu Jan 1 00:00:00 1970 From: Max Waterman Subject: RAID 1 vs RAID 0 Date: Wed, 18 Jan 2006 13:07:16 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; 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've been reading a bit about RAID 1 vs RAID 0 on these pages : They seem to suggest RAID 0 is faster for reading than RAID 1, and I can't figure out why. Clearly, the write performance is worse for RAID 1 than RAID 0 since with RAID 1 that data you are writing at the same time is the same for both drives; but for reading, why can't the two drives be read as if they were a stripe. You could even read the stripe in any 'direction'...when the RAID 1 array has more than two disks, that would make RAID 1 *faster* than RAID 0. ie RAID 0 file is like this 0 1 2 3 4 can only be read in that order : 0 1 2 3 4 but RAID 1 file is like this A B C D E --------- 0 0 0 0 0 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 can be read as A B C D E 0 1 2 3 4 or 1 0 3 4 2 or whatever... Could it not help with small files and when not streaming? Am I missing something? Max.