From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Heflin Subject: raid5 to raid6 reshape never appeared to start, how to cancel/revert Date: Mon, 22 May 2017 13:57:44 -0500 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Sender: linux-raid-owner@vger.kernel.org To: Linux RAID List-Id: linux-raid.ids I had a 3 disk raid5 with a hot spare. I ran this: mdadm --grow /dev/md126 --level=6 --backup-file /root/r6rebuild I suspect I should have changed the number of devices in the above command to 4. The reshape "started" according to /proc/mdstat but never got past block 1, and the time to complete started going up. I did stop the array and have tried to do a revert-reshape but it indicates it will only revert a number of devices change. The backup-file was created on a separate ssd. trying assemble now gets this: mdadm --assemble /dev/md126 /dev/sd[abe]1 /dev/sdd --backup-file=/root/r6rebuild mdadm: Failed to restore critical section for reshape, sorry. examine shows this (sdd was the spare when the --grow was issues) mdadm --examine /dev/sdd /dev/sdd1: Magic : a92b4efc Version : 0.91.00 UUID : 2fb920b1:ce7407fd:dd1a1aa6:74dcda71 Creation Time : Wed May 19 19:04:03 2010 Raid Level : raid6 Used Dev Size : 488384384 (465.76 GiB 500.11 GB) Array Size : 976768768 (931.52 GiB 1000.21 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 126 Reshape pos'n : 0 New Layout : left-symmetric Update Time : Mon May 22 09:25:38 2017 State : clean Internal Bitmap : present Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Checksum : bc406f24 - correct Events : 6140735 Layout : left-symmetric-6 Chunk Size : 64K Number Major Minor RaidDevice State this 3 8 48 3 active /dev/sdd 0 0 8 17 0 active sync /dev/sdb1 1 1 8 65 1 active sync /dev/sde1 2 2 8 1 2 active sync /dev/sda1 3 3 8 48 3 active /dev/sdd mdadm-3.4-2.fc25.x86_64 kernel 4.10.15.200 fc25 fully updated as of 2 days ago. Examine seems to indicate that the reshape never stopped but the revert is unable to cancel this grow even though it did not start at all. The data is not super critical I don't believe I lose anything as this one is being used primarily for backups. It does appear that I added sdd rather than sdd1 but I don't believe that is anything critical to the issue as it should still work fine with the entire disk. Ideas on how to abort the reshape that never started or how to get it to continue? The desired final target is a 4 disk raid6. I have not as of yet rebooted.