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* mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
@ 2012-10-26 20:31 John Drescher
  2012-10-26 21:04 ` Phil Turmel
  0 siblings, 1 reply; 3+ messages in thread
From: John Drescher @ 2012-10-26 20:31 UTC (permalink / raw)
  To: linux-raid

I got the following message when trying to convert a 2 disk raid1 to a
6 disk raid 6 in a 3.3.8 kernel:

fileserver1 btrfs-root # mdadm --grow /dev/md3 --level=6 --raid-devices=6
mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.

Fileserver1 btrfs-root # uname -a
Linux fileserver1 3.3.8-gentoo-fileserver1-raid1 #3 SMP Thu Jul 12
20:06:18 EDT 2012 x86_64 Intel(R) Xeon(R) CPU E31230 @ 3.20GHz
GenuineIntel GNU/Linux

fileserver1 btrfs-root # mdadm --version
mdadm - v3.2.6 - 25th October 2012

fileserver1 btrfs-root # mdadm -D /dev/md3
/dev/md3:
        Version : 1.2
  Creation Time : Wed Sep 28 16:03:56 2011
     Raid Level : raid1
     Array Size : 1874607039 (1787.76 GiB 1919.60 GB)
  Used Dev Size : 1874607039 (1787.76 GiB 1919.60 GB)
   Raid Devices : 2
  Total Devices : 6
    Persistence : Superblock is persistent

    Update Time : Fri Oct 26 16:24:22 2012
          State : clean
 Active Devices : 2
Working Devices : 6
 Failed Devices : 0
  Spare Devices : 4

           Name : fileserver1:3  (local to host fileserver1)
           UUID : df2200d4:3ba5d29c:524dc437:35d663ea
         Events : 785

    Number   Major   Minor   RaidDevice State
       0       8      116        0      active sync   /dev/sdh4
       1       8        4        1      active sync   /dev/sda4

       2       8      244        -      spare   /dev/sdp4
       3       8      196        -      spare   /dev/sdm4
       4       8      212        -      spare   /dev/sdn4
       5       8      228        -      spare   /dev/sdo4


Would upgrading the kernel avoid needing to reduce the size of the
array? If not I assume I have to reduce the size of the btrfs
filesystem then resize the array to 1874604032. Is that correct?

-- 
John M. Drescher

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
  2012-10-26 20:31 mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first John Drescher
@ 2012-10-26 21:04 ` Phil Turmel
  2012-10-26 22:36   ` John Drescher
  0 siblings, 1 reply; 3+ messages in thread
From: Phil Turmel @ 2012-10-26 21:04 UTC (permalink / raw)
  To: John Drescher; +Cc: linux-raid

On 10/26/2012 04:31 PM, John Drescher wrote:
> I got the following message when trying to convert a 2 disk raid1 to a
> 6 disk raid 6 in a 3.3.8 kernel:
> 
> fileserver1 btrfs-root # mdadm --grow /dev/md3 --level=6 --raid-devices=6
> mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
> 
> Fileserver1 btrfs-root # uname -a
> Linux fileserver1 3.3.8-gentoo-fileserver1-raid1 #3 SMP Thu Jul 12
> 20:06:18 EDT 2012 x86_64 Intel(R) Xeon(R) CPU E31230 @ 3.20GHz
> GenuineIntel GNU/Linux
> 
> fileserver1 btrfs-root # mdadm --version
> mdadm - v3.2.6 - 25th October 2012
> 
> fileserver1 btrfs-root # mdadm -D /dev/md3
> /dev/md3:
>         Version : 1.2
>   Creation Time : Wed Sep 28 16:03:56 2011
>      Raid Level : raid1
>      Array Size : 1874607039 (1787.76 GiB 1919.60 GB)
>   Used Dev Size : 1874607039 (1787.76 GiB 1919.60 GB)
>    Raid Devices : 2
>   Total Devices : 6
>     Persistence : Superblock is persistent
> 
>     Update Time : Fri Oct 26 16:24:22 2012
>           State : clean
>  Active Devices : 2
> Working Devices : 6
>  Failed Devices : 0
>   Spare Devices : 4
> 
>            Name : fileserver1:3  (local to host fileserver1)
>            UUID : df2200d4:3ba5d29c:524dc437:35d663ea
>          Events : 785
> 
>     Number   Major   Minor   RaidDevice State
>        0       8      116        0      active sync   /dev/sdh4
>        1       8        4        1      active sync   /dev/sda4
> 
>        2       8      244        -      spare   /dev/sdp4
>        3       8      196        -      spare   /dev/sdm4
>        4       8      212        -      spare   /dev/sdn4
>        5       8      228        -      spare   /dev/sdo4

The "Used Dev Size" must be a multiple of the target chunk size, and the
smallest allowed chunk size is 4K.

> Would upgrading the kernel avoid needing to reduce the size of the
> array? If not I assume I have to reduce the size of the btrfs
> filesystem then resize the array to 1874604032. Is that correct?

Upgrading the kernel won't help.  For a 4K chunk size, 1874607032
sectors is correct.  For other chunk sizes, you'll have to shrink a bit
more (1874607039 == 0x6FBC3BBF).

HTH,

Phil


^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
  2012-10-26 21:04 ` Phil Turmel
@ 2012-10-26 22:36   ` John Drescher
  0 siblings, 0 replies; 3+ messages in thread
From: John Drescher @ 2012-10-26 22:36 UTC (permalink / raw)
  To: Phil Turmel; +Cc: linux-raid

On Fri, Oct 26, 2012 at 5:04 PM, Phil Turmel <philip@turmel.org> wrote:
> On 10/26/2012 04:31 PM, John Drescher wrote:
>> I got the following message when trying to convert a 2 disk raid1 to a
>> 6 disk raid 6 in a 3.3.8 kernel:
>>
>> fileserver1 btrfs-root # mdadm --grow /dev/md3 --level=6 --raid-devices=6
>> mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
>>
>> Fileserver1 btrfs-root # uname -a
>> Linux fileserver1 3.3.8-gentoo-fileserver1-raid1 #3 SMP Thu Jul 12
>> 20:06:18 EDT 2012 x86_64 Intel(R) Xeon(R) CPU E31230 @ 3.20GHz
>> GenuineIntel GNU/Linux
>>
>> fileserver1 btrfs-root # mdadm --version
>> mdadm - v3.2.6 - 25th October 2012
>>
>> fileserver1 btrfs-root # mdadm -D /dev/md3
>> /dev/md3:
>>         Version : 1.2
>>   Creation Time : Wed Sep 28 16:03:56 2011
>>      Raid Level : raid1
>>      Array Size : 1874607039 (1787.76 GiB 1919.60 GB)
>>   Used Dev Size : 1874607039 (1787.76 GiB 1919.60 GB)
>>    Raid Devices : 2
>>   Total Devices : 6
>>     Persistence : Superblock is persistent
>>
>>     Update Time : Fri Oct 26 16:24:22 2012
>>           State : clean
>>  Active Devices : 2
>> Working Devices : 6
>>  Failed Devices : 0
>>   Spare Devices : 4
>>
>>            Name : fileserver1:3  (local to host fileserver1)
>>            UUID : df2200d4:3ba5d29c:524dc437:35d663ea
>>          Events : 785
>>
>>     Number   Major   Minor   RaidDevice State
>>        0       8      116        0      active sync   /dev/sdh4
>>        1       8        4        1      active sync   /dev/sda4
>>
>>        2       8      244        -      spare   /dev/sdp4
>>        3       8      196        -      spare   /dev/sdm4
>>        4       8      212        -      spare   /dev/sdn4
>>        5       8      228        -      spare   /dev/sdo4
>
> The "Used Dev Size" must be a multiple of the target chunk size, and the
> smallest allowed chunk size is 4K.
>
>> Would upgrading the kernel avoid needing to reduce the size of the
>> array? If not I assume I have to reduce the size of the btrfs
>> filesystem then resize the array to 1874604032. Is that correct?
>
> Upgrading the kernel won't help.  For a 4K chunk size, 1874607032
> sectors is correct.  For other chunk sizes, you'll have to shrink a bit
> more (1874607039 == 0x6FBC3BBF).
>

Thanks a lot. I understand.

John

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-10-26 22:36 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2012-10-26 20:31 mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first John Drescher
2012-10-26 21:04 ` Phil Turmel
2012-10-26 22:36   ` John Drescher

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