From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mario 'BitKoenig' Holbe Subject: Re: raid5 or raid6 and the maximum size Date: Thu, 22 Sep 2005 15:52:08 +0200 Message-ID: References: <4332AD95.1080904@bppiac.hu> Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Farkas Levente wrote: > - 7 x 300GB in raid5 and one 300GB spare or > - 8 x 300GB in raid6? > it seems the same to me since both case we can get two disk faild and No, it's everything but the same. raid5 always gives you survival of exactly one simultaneous disk failure. If two of your disks fail simultaneously in a raid5, you're lost. A spare disk gets used not before any disk failed. Then it needs time to get synched, where you have no redundancy at all. After that your raid5 is able to survive another disk failure. regards Mario -- As a rule, the more bizarre a thing is, the less mysterious it proves to be. -- Sherlock Holmes by Arthur Conan Doyle