From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: Best way to create RAID-6 for swap partition - existing one failed Date: Wed, 18 May 2011 17:01:53 +0200 Message-ID: References: <595104.28955.qm@web65106.mail.ac2.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <595104.28955.qm@web65106.mail.ac2.yahoo.com> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 16/05/2011 23:41, Gavin Flower wrote: > Hi, > > Motivation, existing RAID-6 swap partition failed. I am thinking I > should recreate it in a new format, as currently it is 'Version : > 0.90', rather than simply rebuild it. > > So 3 questions: > > (1) What further diagnostics should I run first, if any (note I am > currently running badblocks on the drive that dropped out), and I > have put the existing diagnostic info at the end of this email > > > (2) What is the most appropriate RAID-6 format for a swap partition, > keeping same the number of drives and overall capacity. > > (3) How to convert the existing /dev/md0 to the new format. > > RAID-6 is a lot of overhead for a 5-drive array. Unless you have plans to add more drives or resize it, you are going to get a lot faster performance with a raid-10,far layout at little extra space cost. RAID-6 is particularly slow for small writes, as the whole stripe needs to be read in for an update - I think that would hit swap usage pretty hard.