Re: RAID6 reshape stalls immediately

Anugraha Sinha <asinha.mailinglist@xxxxxxxxx> · Fri, 6 Nov 2015 22:54:44 +0900

Dear Peter,

Also please follow one of the mails over linux-raid mailing list.
Subject : RAID6 reshape stalls immediately

It discusses a similar problem, when giving backup-file.

Regards
Anugraha

On 11/6/2015 10:48 PM, Anugraha Sinha wrote:
Dear Peter,

What happening on the root partition where you are trying to take a backup?

Any I/O, filesize etc?

Also could you share the output of mdadm --examine <all of your 6 raid
members individually?

On 11/5/2015 8:39 AM, Peter Chubb wrote:
Hi Folks,
    I added two disks to my RAID5 array then attempted to reshape it to
    RAID 6.  And it has been sitting on 0% complete, with no disk I/O
    for 24 hours now.

    Is there any way to kick the reshape process?

/proc/mdstat is:

   Personalities : [raid6] [raid5] [raid4]
   md0 : active raid6 sdi1[6] sdh1[5] sdd1[4] sde1[2] sdb1[1] sda1[0]
       5860122624 blocks super 1.2 level 6, 512k chunk, algorithm 18
[6/5] [UUUU_U]
       [>....................]  reshape =  0.0% (0/1953374208)
finish=1308.7min speed=24099K/sec
       bitmap: 0/15 pages [0KB], 65536KB chunk

   unused devices: <none>

What I did:
   mdadm --add /dev/md0 /dev/sdh1
   mdadm --add /dev/md0 /dev/sdi1
   mdadm --grow /dev/md0 --level=6 --raid-devices=6
--backup-file=/root/raid5-backup

dmesg reported:
[691739.298345] md: bind<sdh1>
[691739.364534] RAID conf printout:
[691739.364537]  --- level:5 rd:4 wd:4
[691739.364539]  disk 0, o:1, dev:sda1
[691739.364540]  disk 1, o:1, dev:sdb1
[691739.364541]  disk 2, o:1, dev:sde1
[691739.364542]  disk 3, o:1, dev:sdd1
[691741.832242] md: bind<sdi1>
[691741.898470] RAID conf printout:
[691741.898474]  --- level:5 rd:4 wd:4
[691741.898476]  disk 0, o:1, dev:sda1
[691741.898478]  disk 1, o:1, dev:sdb1
[691741.898480]  disk 2, o:1, dev:sde1
[691741.898481]  disk 3, o:1, dev:sdd1
[691741.898482] RAID conf printout:
[691741.898482]  --- level:5 rd:4 wd:4
[691741.898484]  disk 0, o:1, dev:sda1
[691741.898485]  disk 1, o:1, dev:sdb1
[691741.898486]  disk 2, o:1, dev:sde1
[691741.898487]  disk 3, o:1, dev:sdd1
[691805.469105] md/raid:md0: device sdd1 operational as raid disk 3
[691805.469110] md/raid:md0: device sde1 operational as raid disk 2
[691805.469111] md/raid:md0: device sdb1 operational as raid disk 1
[691805.469112] md/raid:md0: device sda1 operational as raid disk 0
[691805.469551] md/raid:md0: allocated 5424kB
[691805.506035] md/raid:md0: raid level 6 active with 4 out of 5
devices, algori
thm 18
[691805.506050] RAID conf printout:
[691805.506051]  --- level:6 rd:5 wd:4
[691805.506053]  disk 0, o:1, dev:sda1
[691805.506054]  disk 1, o:1, dev:sdb1
[691805.506055]  disk 2, o:1, dev:sde1
[691805.506056]  disk 3, o:1, dev:sdd1
[691805.847329] RAID conf printout:
[691805.847333]  --- level:6 rd:6 wd:5
[691805.847335]  disk 0, o:1, dev:sda1
[691805.847336]  disk 1, o:1, dev:sdb1
[691805.847337]  disk 2, o:1, dev:sde1
[691805.847338]  disk 3, o:1, dev:sdd1
[691805.847340]  disk 4, o:1, dev:sdi1
[691805.847350] RAID conf printout:
[691805.847350]  --- level:6 rd:6 wd:5
[691805.847351]  disk 0, o:1, dev:sda1
[691805.847352]  disk 1, o:1, dev:sdb1
[691805.847353]  disk 2, o:1, dev:sde1
[691805.847354]  disk 3, o:1, dev:sdd1
[691805.847354]  disk 4, o:1, dev:sdi1
[691805.847355]  disk 5, o:1, dev:sdh1
[691805.847424] md: reshape of RAID array md0
[691805.847426] md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
[691805.847428] md: using maximum available idle IO bandwidth (but not
more than 200000 KB/sec) for reshape.
[691805.847439] md: using 128k window, over a total of 1953374208k.

And nothing since.

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