mdadm software raid 5 reshape..

[tgrimley]

Is it possible to stop a reshape (N->N+1 disks) to shutdown and then reboot and resume? Has anyone done this successfully? I haven't managed to find any information on this.

[tgrimley]

in case anyone was curious the answer is yes, you can, but you need an updated version of mdadm to start the rebuild again successfully.

I had the problem listed here: http://ubuntuforums.org/showthread.php?t=833191&highlight=pause+mdadm+reshape&page=2 when I tried to restart so installing the updated .deb worked fine and it's reshaping now :)


root@gutsy:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sdd1[0] sda1[4] sdb1[3] sde1[2] sdc1[1]
1465151616 blocks super 0.91 level 5, 128k chunk, algorithm 2 [5/5] [UUUUU]
[=====>...............] reshape = 27.5% (134593148/488383872) finish=1292.7min speed=4560K/sec

unused devices: <none>

[Rakinos]

Congradulations on that answer being yes. Mdadm does have quite a few nice features that I wish hardware raid controllers had, I just wish that it was a bit more reliable upon reboot (In my experience, one out of 10 reboots would give problems finding all the disks, I think it depended on the order in which they were found by the kernel), and that it had a few more of the features that are found in standard raid controllers.