From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konstantin Svist Subject: messed up changing chunk size Date: Sun, 18 Jul 2010 17:32:25 -0700 Message-ID: <4C439D19.4070906@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids I've been playing around with RAID config and may have finally messed it up. Initially, I created the array with 3 300G drives: # mdadm --create --verbose /dev/md0 --level=5 --raid-devices=3 /dev/sda4 /dev/sdb1 /dev/sdc1 # mkfs.ext4 -v -m 0.01 -E stride=16,stripe-width=32 /dev/md0 It's been working nicely so far, and I decided to add a 4th 300G drive: # mdadm --grow --raid-devices=4 --backup-file=/root/grow_md0.bak /dev/md0 That finished overnight, while I looked around and found that chunk size of 512 should work better. I unmounted the FS and ran # mdadm --grow -c 512 --backup-file=/root/grow_md0_rechunk.bak /dev/md0 mdadm: component size 293033536K is not a multiple of chunksize 512K so I sized it down a bit: # mdadm --grow -z 293033472 --backup-file=/root/grow_md0_size.bak /dev/md0 and then back to resizing chunks: mdadm --grow -c 512 --backup-file=/root/grow_md0_rechunk.bak /dev/md0 It's running right now: # cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 sdd1[3] sda4[0] sdc1[2] sdb1[1] 293033472 blocks super 0.91 level 5, 64k chunk, algorithm 2 [4/4] [UUUU] [====>................] reshape = 22.7% (66540032/293033472) finish=947.3min speed=3984K/sec But just now I tried to mount the filesystem and it's failing: EXT4-fs (md0): bad geometry: block count 146516768 exceeds size of device (73258368 blocks) Here's the question, then: am I royally screwed or is my data still there? How do I recover? Yes, in retrospect I should've probably checked around whether this process has been successful for others.. but that's why they say hindsight is 20/20