On 26/11/17 01:50, Duane wrote:
> I have 3 RAID5 devices. When I assemble them, I end up with a RAID0 device.
>
> What is the cause? What is the solution?
>
> All I can think of is the fact that there is only 1 active device. I had
> 2 but then manually failed it. I want to reassemble a RAID5 array and
> then re-add the second device.
>
OUCH!
Sorry. You have a 3-device raid-5. You only have 1 working device. Your
array is well broken.
You can't "reassemble raid5 then readd the second device". You need to
readd the second device in order to get your raid5 back. I'll let
someone else tell you how, but you need a MINIMUM of two devices to get
your raid working again. Then you need to get your third device added
back otherwise your raid 5 is broken.
DON'T DO ANYTHING WITHOUT ADVICE. I'm sorry, but your message says you
don't understand how raid works, and you are on the verge of destroying
your array irrevocably. It should be a simple recovery, *provided* you
don't make any mistakes.
Cheers,
Wol
>
> mdadm -E /dev/sdc2 /dev/sdd /dev/sde
>
> /dev/sdc2:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x1
> Array UUID : f8c0d29d:9b5986a4:050ca914:3a2fb8c8
> Name : dave:0 (local to host dave)
> Creation Time : Fri Oct 6 10:46:50 2017
> Raid Level : raid5
> Raid Devices : 3
>
> Avail Dev Size : 7813726208 (3725.88 GiB 4000.63 GB)
> Array Size : 7630592 (7.28 GiB 7.81 GB)
> Used Dev Size : 7630592 (3.64 GiB 3.91 GB)
> Data Offset : 262144 sectors
> Super Offset : 8 sectors
> Unused Space : before=262064 sectors, after=7806142351 sectors
> State : clean
> Device UUID : 0fe7e674:e1149499:7acb8853:c71fed62
>
> Internal Bitmap : 8 sectors from superblock
> Update Time : Sun Nov 19 13:53:23 2017
> Bad Block Log : 512 entries available at offset 24 sectors
> Checksum : 79ee1226 - correct
> Events : 51526
>
> Layout : left-symmetric
> Chunk Size : 64K
>
> Device Role : Active device 0
> Array State : A.. ('A' == active, '.' == missing, 'R' == replacing)
> /dev/sdd:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x1
> Array UUID : f8c0d29d:9b5986a4:050ca914:3a2fb8c8
> Name : dave:0 (local to host dave)
> Creation Time : Fri Oct 6 10:46:50 2017
> Raid Level : raid5
> Raid Devices : 3
>
> Avail Dev Size : 7813709489 (3725.87 GiB 4000.62 GB)
> Array Size : 7630592 (7.28 GiB 7.81 GB)
> Used Dev Size : 7630592 (3.64 GiB 3.91 GB)
> Data Offset : 262144 sectors
> Super Offset : 8 sectors
> Unused Space : before=262064 sectors, after=7806078897 sectors
> State : clean
> Device UUID : ce2c8c03:f47f505b:c9a34e9a:668b70f5
>
> Internal Bitmap : 8 sectors from superblock
> Update Time : Sun Nov 19 13:53:23 2017
> Bad Block Log : 512 entries available at offset 16 sectors
> Checksum : a398c591 - correct
> Events : 51526
>
> Layout : left-symmetric
> Chunk Size : 64K
>
> Device Role : spare
> Array State : A.. ('A' == active, '.' == missing, 'R' == replacing)
> /dev/sde:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x1
> Array UUID : f8c0d29d:9b5986a4:050ca914:3a2fb8c8
> Name : dave:0 (local to host dave)
> Creation Time : Fri Oct 6 10:46:50 2017
> Raid Level : raid5
> Raid Devices : 3
>
> Avail Dev Size : 7813709489 (3725.87 GiB 4000.62 GB)
> Array Size : 7630592 (7.28 GiB 7.81 GB)
> Used Dev Size : 7630592 (3.64 GiB 3.91 GB)
> Data Offset : 262144 sectors
> Super Offset : 8 sectors
> Unused Space : before=262064 sectors, after=7806078897 sectors
> State : clean
> Device UUID : aecb9ce3:e7bc161f:9b8d1764:db815dde
>
> Internal Bitmap : 8 sectors from superblock
> Update Time : Sun Nov 19 13:53:23 2017
> Bad Block Log : 512 entries available at offset 16 sectors
> Checksum : fa2581ac - correct
> Events : 51526
>
> Layout : left-symmetric
> Chunk Size : 64K
>
> Device Role : spare
> Array State : A.. ('A' == active, '.' == missing, 'R' == replacing)
>
>
> mdadm -D /dev/md0
> /dev/md0:
> Version : 1.2
> Raid Level : raid0
> Total Devices : 3
> Persistence : Superblock is persistent
>
> State : inactive
>
> Name : dave:0 (local to host dave)
> UUID : f8c0d29d:9b5986a4:050ca914:3a2fb8c8
> Events : 51526
>
> Number Major Minor RaidDevice
>
> - 8 64 - /dev/sde
> - 8 34 - /dev/sdc2
> - 8 48 - /dev/sdd
>
>
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