Moved disks to a RAID controller; can't bring back the software RAID5

Hiya,

I have 4 drives of 2TB, previously connected directly to the motherboard SATA controller and configured in a RAID5 matrix under OMV. Recently I purchased a HP P410 SAS/SATA RAID controller for some extra kick. Today I connected the disks to the controller and ran into trouble: I can't bring up the RAID5 matrix for an unknown reason.

The controller is configured with each drive in its own array and a single logical drive. Basically, it bypasses any built-in RAID functionality and exposes the disks as JBOD to the operating system. They just appear with a different name - instead of seeing their model, firmware etc. now I see "Logical volume" for all as Model.

Here's what I'm getting:

mdadm --assemble /dev/md127 /dev/sd[abcd] --verbose --force

Zitat

mdadm: looking for devices for /dev/md127
mdadm: /dev/sda is identified as a member of /dev/md127, slot 2.
mdadm: /dev/sdb is identified as a member of /dev/md127, slot 1.
mdadm: /dev/sdc is identified as a member of /dev/md127, slot 0.
mdadm: /dev/sdd is identified as a member of /dev/md127, slot 3.
mdadm: failed to add /dev/sdb to /dev/md127: Invalid argument
mdadm: failed to add /dev/sda to /dev/md127: Invalid argument
mdadm: failed to add /dev/sdd to /dev/md127: Invalid argument
mdadm: failed to add /dev/sdc to /dev/md127: Invalid argument
mdadm: failed to RUN_ARRAY /dev/md127: Invalid argument

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If I look in the system log, I get the following:

Zitat

Nov 9 22:23:57 openmediavault kernel: [34998.542934] md: md127 stopped.
Nov 9 22:23:57 openmediavault kernel: [34998.553682] md: sdb does not have a valid v1.2 superblock, not importing!
Nov 9 22:23:57 openmediavault kernel: [34998.553719] md: md_import_device returned -22
Nov 9 22:23:57 openmediavault kernel: [34998.554317] md: sda does not have a valid v1.2 superblock, not importing!
Nov 9 22:23:57 openmediavault kernel: [34998.554353] md: md_import_device returned -22
Nov 9 22:23:57 openmediavault kernel: [34998.555458] md: sdd does not have a valid v1.2 superblock, not importing!
Nov 9 22:23:57 openmediavault kernel: [34998.555494] md: md_import_device returned -22
Nov 9 22:23:57 openmediavault kernel: [34998.557131] md: sdc does not have a valid v1.2 superblock, not importing!
Nov 9 22:23:57 openmediavault kernel: [34998.557168] md: md_import_device returned -22

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I'm baffled, as I can check each drive with mdadm, but can't bring up the array. Any ideas, please?

Here are some other results:

blkid

Zitat

/dev/sda: UUID="88e0c6ad-c867-07dc-4db9-c4d4c8c2faa6" UUID_SUB="212abc31-f6ba-f282-c10a-fdcfeedb489f" LABEL="openmediavault:Storage" TYPE="linux_raid_member"
/dev/sdb: UUID="88e0c6ad-c867-07dc-4db9-c4d4c8c2faa6" UUID_SUB="ef380a3b-8a8a-76d1-1886-b090946d5e7e" LABEL="openmediavault:Storage" TYPE="linux_raid_member"
/dev/sdc: UUID="88e0c6ad-c867-07dc-4db9-c4d4c8c2faa6" UUID_SUB="82dbfa20-73b3-302a-b8fb-9ddafb554983" LABEL="openmediavault:Storage" TYPE="linux_raid_member"
/dev/sdd: UUID="88e0c6ad-c867-07dc-4db9-c4d4c8c2faa6" UUID_SUB="7627ad4d-87bd-7f76-2094-a4f1973fe32c" LABEL="openmediavault:Storage" TYPE="linux_raid_member"
/dev/sdh1: UUID="cc47e1e0-b1ee-4e49-aa7c-d28581c68817" TYPE="ext4"
/dev/sdh5: UUID="ed1f5117-4fe9-4b88-8137-fc20a06e9ade" TYPE="swap"

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cat /proc/mdstat

Zitat

Personalities :
unused devices: <none>

mdadm --examine /dev/sd[a-d]

Zitat

/dev/sda:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 88e0c6ad:c86707dc:4db9c4d4:c8c2faa6
Name : openmediavault:Storage (local to host openmediavault)
Creation Time : Wed Aug 8 03:13:00 2012
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB)
Array Size : 5860535808 (5589.04 GiB 6001.19 GB)
Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB)
Data Offset : 4096 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 212abc31:f6baf282:c10afdcf:eedb489f

Update Time : Sun Nov 9 10:04:22 2014
Checksum : 4a0e4b27 - correct
Events : 1492

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 2
Array State : AAAA ('A' == active, '.' == missing)
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 88e0c6ad:c86707dc:4db9c4d4:c8c2faa6
Name : openmediavault:Storage (local to host openmediavault)
Creation Time : Wed Aug 8 03:13:00 2012
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)
Array Size : 5860535808 (5589.04 GiB 6001.19 GB)
Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : ef380a3b:8a8a76d1:1886b090:946d5e7e

Update Time : Sun Nov 9 10:04:22 2014
Checksum : 41a93683 - correct
Events : 1492

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing)
/dev/sdc:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 88e0c6ad:c86707dc:4db9c4d4:c8c2faa6
Name : openmediavault:Storage (local to host openmediavault)
Creation Time : Wed Aug 8 03:13:00 2012
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)
Array Size : 5860535808 (5589.04 GiB 6001.19 GB)
Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 82dbfa20:73b3302a:b8fb9dda:fb554983

Update Time : Sun Nov 9 10:04:22 2014
Checksum : cf2c6004 - correct
Events : 1492

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing)
/dev/sdd:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 88e0c6ad:c86707dc:4db9c4d4:c8c2faa6
Name : openmediavault:Storage (local to host openmediavault)
Creation Time : Wed Aug 8 03:13:00 2012
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)
Array Size : 5860535808 (5589.04 GiB 6001.19 GB)
Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 7627ad4d:87bd7f76:2094a4f1:973fe32c

Update Time : Sun Nov 9 10:04:22 2014
Checksum : 8ce3814 - correct
Events : 1492

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 3
Array State : AAAA ('A' == active, '.' == missing)

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Hm, or I could just connect those drives back to the on-board SATA controller, bring up the RAID5 matrix, and complete the data backup.

The objective is to transfer the data from those drives so that I can set them up as a RAID5 matrix managed by the RAID controller card, and presented to the OS as a single volume.

Welp, I think I can mark this as "Solved" by applying the workaround above. Currently the 4 disks are connected back to the motherboard built-in SATA controller, software RAID working fine, and transferring data to other drives connected to the hardware RAID card. The sustained 70 MB/s copying speed is a lot better than 16 MB/s when backup disks were connected in a USB(2) external rack. Plus, the partitioning of those disks somehow messed up the partition table, so the backups were not actually retrievable So much for trusting USB racks.

Tonight's fun: after all data is backed up, move the 4 disks to the RAID card and set up a RAID5 there. It has a specialized CPU for accelerating this, dedicated 512MB of ECC RAM, battery backup and a plethora of built-in tools for early identification and recovery from failures. Software RAID might be "free", but when a server-grade hardware RAID controller with all the bells and whistles is under €150...