From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Hardy Subject: Re: [PATCH md 9 of 9] Optimise reconstruction when re-adding a recently failed drive. Date: Thu, 17 Feb 2005 16:51:27 -0800 Message-ID: <42153C0F.1030904@h3c.com> References: <20050218111131.790.patches@notabene> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids NeilBrown wrote: > When an array is degraded, bit in the intent-bitmap are > never cleared. So if a recently failed drive is re-added, we only need > to reconstruct the block that are still reflected in the > bitmap. > This patch adds support for this re-adding. Hi there - If I understand this correctly, this means that: 1) if I had a raid1 mirror (for example) that has no writes to it since a resync 2) a drive fails out, and some writes occur 3) when I re-add the drive, only the areas where the writes occurred would be re-synced? I can think of a bunch of peripheral questions around this scenario, and bad sectors / bad sector clearing, but I may not be understanding the basic idea, so I wanted to ask first. -Mike