From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: Reshaping raid0/10 Date: Mon, 28 May 2007 21:51:16 -0700 Message-ID: <465BB144.2060003@zytor.com> References: <17884.42154.248251.261955@notabene.brown> <17887.19400.179239.281711@notabene.brown> <45F3134C.7070500@zytor.com> <17908.33911.135761.236374@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17908.33911.135761.236374@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Jan Engelhardt , linux-raid@vger.kernel.org List-Id: linux-raid.ids Back in March, Neil Brown wrote: > > Well.... it's not straight forward at all. > > Firstly: it can only work if all your drives are the same size > (rounded to 64K). If they aren't raid0 will use all the available > space on each drive, while raid5 will only use the amount that is > available on the first drive. > > If that condition is met, then you can safely convert to a raid4 with > one extra (missing) device by simply creating an array with the same > drives (so you have to stop and restart the array - you cannot do that > bit while the array is live). You seem to need --assume-clean > to create the raid4 degraded... That is probably a bug in mdadm. > [rest of procedure deleted] I just wanted to let you know we performed this procedure on mirrors1.kernel.org. It was successful, and saved us from copying 3 TB of data across the Internet. -hpa