Is it correct that raid5 cannot be converted from Consistency Policy: bitmap to ppl?

Is it correct that raid5 cannot be converted from Consistency Policy: bitmap to ppl?

[Marc MERLIN]

Is there any way around this, or not without a full reformat/rebuild?

gargamel:~# mdadm --query --detail /dev/md5
/dev/md5:
           Version : 1.2
     Creation Time : Tue Jan 21 10:35:52 2014
        Raid Level : raid5
        Array Size : 15627542528 (14903.59 GiB 16002.60 GB)
     Used Dev Size : 3906885632 (3725.90 GiB 4000.65 GB)
      Raid Devices : 5
     Total Devices : 5
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Sun Jul  3 03:02:01 2022
             State : active, checking 
    Active Devices : 5
   Working Devices : 5
    Failed Devices : 0
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : bitmap

      Check Status : 99% complete

              Name : gargamel.svh.merlins.org:5  (local to host gargamel.svh.merlins.org)
              UUID : ec672af7:a66d9557:2f00d76c:38c9f705
            Events : 642977

    Number   Major   Minor   RaidDevice State
       0       8      193        0      active sync   /dev/sdm1
       6       8      177        1      active sync   /dev/sdl1
       2       8      209        2      active sync   /dev/sdn1
       3       8        1        3      active sync   /dev/sda1
       5       8       17        4      active sync   /dev/sdb1
gargamel:~# mdadm --grow --consistency-policy=ppl /dev/md5
mdadm: Current consistency policy is bitmap, cannot change to ppl

Kernel 5.16.

Thanks,
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
 
Home page: http://marc.merlins.org/                       | PGP 7F55D5F27AAF9D08

Re: Is it correct that raid5 cannot be converted from Consistency Policy: bitmap to ppl?

[Wols Lists]

On 03/07/2022 21:07, Marc MERLIN wrote:
> Is there any way around this, or not without a full reformat/rebuild?

Not sure, but I expect there is ... is this the collision between 
journal and bitmap? I know it won't let you mix those.

Look at the wiki, it tells you how to get rid of the bitmap, and then 
you can probably change it to pol.

Cheers,
Wol

https://raid.wiki.kernel.org/index.php/Linux_Raid
> 
> gargamel:~# mdadm --query --detail /dev/md5
> /dev/md5:
>             Version : 1.2
>       Creation Time : Tue Jan 21 10:35:52 2014
>          Raid Level : raid5
>          Array Size : 15627542528 (14903.59 GiB 16002.60 GB)
>       Used Dev Size : 3906885632 (3725.90 GiB 4000.65 GB)
>        Raid Devices : 5
>       Total Devices : 5
>         Persistence : Superblock is persistent
> 
>       Intent Bitmap : Internal
> 
>         Update Time : Sun Jul  3 03:02:01 2022
>               State : active, checking
>      Active Devices : 5
>     Working Devices : 5
>      Failed Devices : 0
>       Spare Devices : 0
> 
>              Layout : left-symmetric
>          Chunk Size : 512K
> 
> Consistency Policy : bitmap
> 
>        Check Status : 99% complete
> 
>                Name : gargamel.svh.merlins.org:5  (local to host gargamel.svh.merlins.org)
>                UUID : ec672af7:a66d9557:2f00d76c:38c9f705
>              Events : 642977
> 
>      Number   Major   Minor   RaidDevice State
>         0       8      193        0      active sync   /dev/sdm1
>         6       8      177        1      active sync   /dev/sdl1
>         2       8      209        2      active sync   /dev/sdn1
>         3       8        1        3      active sync   /dev/sda1
>         5       8       17        4      active sync   /dev/sdb1
> gargamel:~# mdadm --grow --consistency-policy=ppl /dev/md5
> mdadm: Current consistency policy is bitmap, cannot change to ppl
> 
> Kernel 5.16.
> 
> Thanks,
> Marc

Re: Is it correct that raid5 cannot be converted from Consistency Policy: bitmap to ppl?

[Lukasz Florczak]

On Sun, 3 Jul 2022 13:07:41 -0700, Marc MERLIN <marc@merlins.org> wrote:

> Is there any way around this, or not without a full reformat/rebuild?
> 
Hi,
I've been able to change the consistency using mdadm v4.2 on a imsm
container. I don't know if it will work for native metadata. Hope this
helps you a little.

The steps I did it:
1. Stop the volume
# mdadm -S /dev/md/<volume_name>
2. Update to ppl
# mdadm --update-subarray=0 --update=ppl /dev/md/<container_name>
3. Assemble incrementally
# mdadm --incremental /dev/md/<container_name>

Thanks,
Lukasz

> gargamel:~# mdadm --query --detail /dev/md5
> /dev/md5:
>            Version : 1.2
>      Creation Time : Tue Jan 21 10:35:52 2014
>         Raid Level : raid5
>         Array Size : 15627542528 (14903.59 GiB 16002.60 GB)
>      Used Dev Size : 3906885632 (3725.90 GiB 4000.65 GB)
>       Raid Devices : 5
>      Total Devices : 5
>        Persistence : Superblock is persistent
> 
>      Intent Bitmap : Internal
> 
>        Update Time : Sun Jul  3 03:02:01 2022
>              State : active, checking 
>     Active Devices : 5
>    Working Devices : 5
>     Failed Devices : 0
>      Spare Devices : 0
> 
>             Layout : left-symmetric
>         Chunk Size : 512K
> 
> Consistency Policy : bitmap
> 
>       Check Status : 99% complete
> 
>               Name : gargamel.svh.merlins.org:5  (local to host
> gargamel.svh.merlins.org) UUID : ec672af7:a66d9557:2f00d76c:38c9f705
>             Events : 642977
> 
>     Number   Major   Minor   RaidDevice State
>        0       8      193        0      active sync   /dev/sdm1
>        6       8      177        1      active sync   /dev/sdl1
>        2       8      209        2      active sync   /dev/sdn1
>        3       8        1        3      active sync   /dev/sda1
>        5       8       17        4      active sync   /dev/sdb1
> gargamel:~# mdadm --grow --consistency-policy=ppl /dev/md5
> mdadm: Current consistency policy is bitmap, cannot change to ppl
> 
> Kernel 5.16.
> 
> Thanks,
> Marc
> -- 
> "A mouse is a device used to point at the xterm you want to type in"
> - A.S.R. 
> Home page: http://marc.merlins.org/                       | PGP
> 7F55D5F27AAF9D08