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RAID disks in random order
I have a PERC H740P Adapter with firmware version 5.050.00-1705 and driver version 07.713.01.00-rc1 (as reported by perccli64).
This adapter used to have 8 disks arranged in two RAID5 arrays of 4 disks each.
All 8 disks were removed and then re-inserted in the adapter slots but in random order (don't ask). The adapter did not recognize them and they are now all showing as "Unconfigured Good":
PD LIST :
=======
---------------------------------------------------------------------------
EID:Slt DID State DG Size Intf Med SED PI SeSz Model Sp
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64:0 0 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:1 1 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:2 2 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:3 3 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:4 4 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:5 5 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:6 6 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
64:7 7 UGood - 7.276 TB SATA HDD N N 512B HGST HUS728T8TALE6L0 U
How can I identify which disks belong to the two original arrays, and reinstantiate the arrays?
Thanks a lot
alfiopuglisi
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August 19th, 2024 12:06
Update: the virtual disks were deleted before removing the physical disks, however no other update to the disks was made, so the data should still be there and recoverable somehow
Origin3k
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August 19th, 2024 13:55
If you delete the VDs the config witin the PERC and on the Disks are removed and your data is gone.
If you remove the disks before deleting the VDs than you its possible to import the "foreign" config.
Regards,
Joerg
alfiopuglisi
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August 19th, 2024 14:46
@Origin3k What happens if I recreate the VDs again in PERC in RAID5? Will it pick up the existing data on the disks or erase them and start from scratch?
Origin3k
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August 19th, 2024 15:47
You have insert the disks in random order. You cant recreated a "shadow" VD on unknown Disks.
DELL-Charles R
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August 19th, 2024 17:38
Hello,
As Origin3k mention, you have deleted the array's from the drive. The configuration no longer exist.
I recommend to check your backup. If this is critical data and you don't have a backup you may consider a Drive Recovery company to try to retrieve the data if it is possible at all.
If you do have a backup then you can create two new RAID5 with four drives each and restore data to new virtual disks.
alfiopuglisi
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August 20th, 2024 08:39
@DELL-Charles R Thanks for the answer, backups exists but unfortunately they only are partial.
We are thinking that it might be possible to copy the hard disk data and look with at the RAID superblock with an hex editor, or replicate the parity calculation in software. Is there any documentation on the low-level RAID format on disk (superblock and RAID striping/parity) for this controller?
DELL-Charles R
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August 20th, 2024 12:18
Hello,
If you can do that then it may be worth a try.
Dell does not do Data Recovery and I have no low-level format tools.
That is why I recommended you check in to a Data Recovery company if the data is critical and you do not have a backup.
alfiopuglisi
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August 22nd, 2024 15:21
@Origin3k
@DELL-Charles R We managed to recover all data by
- dumping the disks contents to image files
- using an hex editor to derive the RAID5 configuration parameters
- writing some small utilities to replicate the RAID5 calculation in software and extract the data
probably the same thing as the Data Reconvery company would have done, but a lot more fun and surely cheaper :)
Origin3k
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August 22nd, 2024 21:01
Thats sounds great! Good to hear you got your data back!