From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Robinson Subject: Re: Raid 5 - not clean and then a failure. Date: Wed, 26 Aug 2009 13:47:13 +0100 Message-ID: <4A952ED1.8040305@anonymous.org.uk> References: <73066.92033.qm@web51304.mail.re2.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <73066.92033.qm@web51304.mail.re2.yahoo.com> Sender: linux-raid-owner@vger.kernel.org To: Jon@eHardcastle.com Cc: Linux RAID List-Id: linux-raid.ids On 26/08/2009 12:29, Jon Hardcastle wrote: [...] > I did look into bitmaps *abit* i could easily have the imagine for my 6 drive raid 5 stored on the raid1 I have in the same system.. The googling I did tho did not paint a pretty picture it talked about huge performance hits? There is a performance hit but it can be minimised by picking a bitmap chunk size to suit; I ended up getting about 80% of bitmap-less write performance using a 16MB bitmap chunk size instead of about 40% with the default size, on my 3-drive RAID-5 array. Cheers, John.