From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wols Lists Subject: Re: linux raid wiki - backup files Date: Sun, 20 Nov 2016 14:48:25 +0000 Message-ID: <5831B7B9.8090008@youngman.org.uk> References: <583077D0.5070804@youngman.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Phil Turmel , linux-raid List-Id: linux-raid.ids On 20/11/16 00:27, Phil Turmel wrote: > Yes. But the new stripes lay on top of the old stripes, unless you move > the data offset. Which is why a backup file holds the old stripe just > in case. If you can move the offset, you use the lower offset for the > lower addresses in the array, and the higher offset for the higher > addresses, on either side of the reshape position. Okay, understood. So v0.9 and v1.0 always need a backup for a reshape. But if we have a data offset with v1.2, a reshape will use that space if it can rather than needing a backup file? (And changing topic slightly, that space is also used for an internal bitmap?) Cheers, Wol