From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wakko Warner Subject: Shrinking an array Date: Mon, 10 Apr 2017 20:30:08 -0400 Message-ID: <20170411003008.GA18538@animx.eu.org> Reply-To: Wakko Warner Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids I have a question about shrinking an array. My current array is 4x 2tb disks in raid6 (md0). The array was created on the 2nd partition of each disk and spans most of the disk. I would like to replace the 2tb disks with 750gb disks. md0 is a luks container with lvm underneath. I have less than 1tb actually in use. What would the recommended procedure be for shrinking this? I've watched this list, but I don't think I've come across anyone actually wanting to do this before. I'm thinking of these steps already: 1) Shrink PV. 2) Shrink luks. I'm aware that there is not size metadata, but the dm mapping would need to be shrunk. 3) Shrink md0. I did this once when I changed a 6 drive raid6 into a 5 drive raid6. Would I use --array-size= or --size= ? I understand the difference is the size of md0 vs the individual members. So for number 4, if md0 is now small enough, will it accept a member that is smaller? If so, I should beable to add the member to the array and issue --replace. Thanks. -- Microsoft has beaten Volkswagen's world record. Volkswagen only created 22 million bugs.