* How to enable bitmap on IMSM?
@ 2022-06-14 9:14 Roman Mamedov
2022-06-14 14:45 ` Mariusz Tkaczyk
0 siblings, 1 reply; 2+ messages in thread
From: Roman Mamedov @ 2022-06-14 9:14 UTC (permalink / raw)
To: linux-raid
Hello,
I upgraded mdadm to 4.2 to get the bitmap support in IMSM.
I run: "mdadm --update-subarray=0 -U bitmap /dev/md127"
However the array details stay the same, with "Consistency Policy : resync".
No error is reported, and nothing in dmesg.
How to actually use it?
Thanks
# mdadm --detail /dev/md127
/dev/md127:
Version : imsm
Raid Level : container
Total Devices : 4
Working Devices : 4
UUID : d07837ca:804cf5e3:01c52352:f64b0524
Member Arrays : /dev/md/Volume0
Number Major Minor RaidDevice
- 8 32 - /dev/sdc
- 8 0 - /dev/sda
- 8 48 - /dev/sdd
- 8 16 - /dev/sdb
# mdadm --detail /dev/md126
/dev/md126:
Container : /dev/md/imsm0, member 0
Raid Level : raid10
Array Size : 1953519616 (1863.02 GiB 2000.40 GB)
Used Dev Size : 976759808 (931.51 GiB 1000.20 GB)
Raid Devices : 4
Total Devices : 4
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Layout : near=2
Chunk Size : 64K
Consistency Policy : resync
UUID : xxx
Number Major Minor RaidDevice State
3 8 0 0 active sync set-A /dev/sda
2 8 16 1 active sync set-B /dev/sdb
1 8 32 2 active sync set-A /dev/sdc
0 8 48 3 active sync set-B /dev/sdd
# mdadm --update-subarray=0 -U bitmap /dev/md127
# mdadm --detail /dev/md127
/dev/md127:
Version : imsm
Raid Level : container
Total Devices : 4
Working Devices : 4
UUID : d07837ca:804cf5e3:01c52352:f64b0524
Member Arrays : /dev/md/Volume0
Number Major Minor RaidDevice
- 8 32 - /dev/sdc
- 8 0 - /dev/sda
- 8 48 - /dev/sdd
- 8 16 - /dev/sdb
# mdadm --detail /dev/md126
/dev/md126:
Container : /dev/md/imsm0, member 0
Raid Level : raid10
Array Size : 1953519616 (1863.02 GiB 2000.40 GB)
Used Dev Size : 976759808 (931.51 GiB 1000.20 GB)
Raid Devices : 4
Total Devices : 4
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Layout : near=2
Chunk Size : 64K
Consistency Policy : resync
UUID : xxx
Number Major Minor RaidDevice State
3 8 0 0 active sync set-A /dev/sda
2 8 16 1 active sync set-B /dev/sdb
1 8 32 2 active sync set-A /dev/sdc
0 8 48 3 active sync set-B /dev/sdd
--
With respect,
Roman
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: How to enable bitmap on IMSM?
2022-06-14 9:14 How to enable bitmap on IMSM? Roman Mamedov
@ 2022-06-14 14:45 ` Mariusz Tkaczyk
0 siblings, 0 replies; 2+ messages in thread
From: Mariusz Tkaczyk @ 2022-06-14 14:45 UTC (permalink / raw)
To: Roman Mamedov; +Cc: linux-raid
On Tue, 14 Jun 2022 14:14:42 +0500
Roman Mamedov <rm@romanrm.net> wrote:
> Hello,
>
> I upgraded mdadm to 4.2 to get the bitmap support in IMSM.
>
> I run: "mdadm --update-subarray=0 -U bitmap /dev/md127"
> However the array details stay the same, with "Consistency Policy : resync".
> No error is reported, and nothing in dmesg.
>
> How to actually use it?
>
Hi Roman,
There is a bug in mdadm (will be fixed soon) which allows you to update
subarray on active volume. Update is successful but mdmon will overwrite
it.
To enable bitmap, you need to stop member array first:
# mdadm -S /dev/md126
then run update command:
# mdadm --update-subarray=0 -U bitmap /dev/md127
mdadm will set bitmap in metadata:
#mdadm -E /dev/md127
At the end, start member volume:
# mdadm -As
Now, you can verify array details:
# mdadm -D /dev/md126.
Hope it helps,
Mariusz
> Thanks
>
>
> # mdadm --detail /dev/md127
> /dev/md127:
> Version : imsm
> Raid Level : container
> Total Devices : 4
>
> Working Devices : 4
>
>
> UUID : d07837ca:804cf5e3:01c52352:f64b0524
> Member Arrays : /dev/md/Volume0
>
> Number Major Minor RaidDevice
>
> - 8 32 - /dev/sdc
> - 8 0 - /dev/sda
> - 8 48 - /dev/sdd
> - 8 16 - /dev/sdb
>
> # mdadm --detail /dev/md126
> /dev/md126:
> Container : /dev/md/imsm0, member 0
> Raid Level : raid10
> Array Size : 1953519616 (1863.02 GiB 2000.40 GB)
> Used Dev Size : 976759808 (931.51 GiB 1000.20 GB)
> Raid Devices : 4
> Total Devices : 4
>
> State : active
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
>
> Layout : near=2
> Chunk Size : 64K
>
> Consistency Policy : resync
>
>
> UUID : xxx
> Number Major Minor RaidDevice State
> 3 8 0 0 active sync set-A /dev/sda
> 2 8 16 1 active sync set-B /dev/sdb
> 1 8 32 2 active sync set-A /dev/sdc
> 0 8 48 3 active sync set-B /dev/sdd
>
> # mdadm --update-subarray=0 -U bitmap /dev/md127
>
> # mdadm --detail /dev/md127
> /dev/md127:
> Version : imsm
> Raid Level : container
> Total Devices : 4
>
> Working Devices : 4
>
>
> UUID : d07837ca:804cf5e3:01c52352:f64b0524
> Member Arrays : /dev/md/Volume0
>
> Number Major Minor RaidDevice
>
> - 8 32 - /dev/sdc
> - 8 0 - /dev/sda
> - 8 48 - /dev/sdd
> - 8 16 - /dev/sdb
>
> # mdadm --detail /dev/md126
> /dev/md126:
> Container : /dev/md/imsm0, member 0
> Raid Level : raid10
> Array Size : 1953519616 (1863.02 GiB 2000.40 GB)
> Used Dev Size : 976759808 (931.51 GiB 1000.20 GB)
> Raid Devices : 4
> Total Devices : 4
>
> State : active
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
>
> Layout : near=2
> Chunk Size : 64K
>
> Consistency Policy : resync
>
>
> UUID : xxx
> Number Major Minor RaidDevice State
> 3 8 0 0 active sync set-A /dev/sda
> 2 8 16 1 active sync set-B /dev/sdb
> 1 8 32 2 active sync set-A /dev/sdc
> 0 8 48 3 active sync set-B /dev/sdd
>
>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-06-14 9:14 How to enable bitmap on IMSM? Roman Mamedov
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