From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Friesen Subject: RFC: use TRIM data from filesystems to speed up array rebuild? Date: Tue, 04 Sep 2012 12:06:26 -0600 Message-ID: <50464322.3010509@genband.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: Neil Brown , linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi, I'm not really a filesystem guy so this may be a really dumb question. We currently have an issue where we have a ~1TB RAID1 array that is mostly given over to LVM. If we swap one of the disks it will rebuild everything, even though we may only be using a small fraction of the space. This got me thinking. Has anyone given thought to using the TRIM information from filesystems to allow the RAID code to maintain a bitmask of used disk blocks and only sync the ones that are actually used? Presumably this bitmask would itself need to be stored on the disk. Thanks, Chris -- Chris Friesen Software Designer 3500 Carling Avenue Ottawa, Ontario K2H 8E9 www.genband.com