From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: Growing a raid 6 array Date: Fri, 2 Mar 2007 12:59:13 +1100 Message-ID: <17895.34033.867599.954940@notabene.brown> References: <45E72549.2080108@unix-scripts.info> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Justin Piszcz on Thursday March 1 Sender: linux-raid-owner@vger.kernel.org To: Justin Piszcz Cc: Laurent CARON , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thursday March 1, jpiszcz@lucidpixels.com wrote: > You can only grow a RAID5 array in Linux as of 2.6.20 AFAIK. There are two dimensions for growth. You can increase the amount of each device that is used, or you can increase the number of devices. You are correct that increasing the number of devices only works for RAID5 (and RAID1, but you don't get extra space) in 2.6.20 (RAID6 coming in 2.6.21). However this question is about growing an array the first way: increasing the amount of space used on each devices, and that is supported for RAID1/4/5/6. And Laurent: 1/ Yes, it is that easy 2/ I doubt a nearly-full ext3 array increases the risk 3/ The effect of adding a bitmap is that if you suffer a crash while the array is degraded, it will resync faster so you have less exposure to multiple failure. NeilBrown