I eff'd up - 3 dead HDDs at once. Have two parities on a 13 disk array. What can be salvaged?

[gravyrobbers91]

As the title states, I fucked up and forgot to turn off the PSU before taking components out. Unplugged the daisy chain leading to the 5.25" hot swap bay for 3 of my drives. Now none of them spin up. No noise. No movement. Cold as ice. 

 

My understanding is the PCBs are dead. 

 

How much - if any - of my data will be saved from a rebuild if I have 2 parities.  It's 13 disks total. All 4TB. 2 parities, 11 array. 

 

From my understanding, I can order replacement PCB boards for the HDDs, but this should only be done for data recovery, and not reinstating the drives into the array. So I'd still need to figure out how to recover the data and easily bring it back onto the array.  

 

If the parities should be enough to save me when rebuilding with new drives, then I probably won't worry about the PCB issue

[itimpi]

With 3 dead drives and only 2 parity drives then parity will not help you as you cannot run a rebuild in that state.   In principle you should consider the content of those 3 dead drives lost unless a PCB swap can bring them back to life.    You did not mention if the 3 drives were all data drives, or if any of them were parity drives?

 

What is the state of your backups?   That might help with determining if it is worth trying get the drives resurrected via a PCB swap.

 

in the short term you can rebuild your array without the content of the 3 dead drives, and later if they are resurrected copy their content back into the array.

[gravyrobbers91]

7 minutes ago, itimpi said:

With 3 dead drives and only 2 parity drives then parity will not help you as you cannot run a rebuild in that state.   In principle you should consider the content of those 3 dead drives lost unless a PCB swap can bring them back to life.    You did not mention if the 3 drives were all data drives, or if any of them were parity drives?

 

What is the state of your backups?   That might help with determining if it is worth trying get the drives resurrected via a PCB swap.

 

in the short term you can rebuild your array without the content of the 3 dead drives, and later if they are resurrected copy their content back into the array.

Right. The 3 drives that failed were not parity drives. I guess the other question is, even if 2 parity drives can’t rebuild all the data lost in the 3 drives, will it at least rebuild some, or is it an all or nothing kind of thing. 
 

If it will rebuild what it can, then I think the best course may be to rebuild with 3 new drives, see what’s lost, and if it’s vital then swap the PCBs and bring that data back into the array. 
 

I do know those were more recent drives at the very least. But they were still installed awhile ago. 

[itimpi]

No - it is an all or nothing scenario.    A rebuild with 2 parity drives requires all except a max of 2 failed drives to be read reliably for the rebuild to work.   With 3 failed drives this is not possible.

 

[gravyrobbers91]

7 hours ago, itimpi said:

No - it is an all or nothing scenario.    A rebuild with 2 parity drives requires all except a max of 2 failed drives to be read reliably for the rebuild to work.   With 3 failed drives this is not possible.

 

 

Word. 

 

So first off - Picking up some new drives, WD Blue, same as one of the drives that failed. I'm not expecting it, but if it's the same PCB board, I'm gonna see if swapping the boards will let me run that failed WD drive. IF I can get that to run, even slowly, then I've got only 2 actually dead drives, and I can rebuild the array, then swap the WD with the good one, and rebuild again. 

 

Reality - I probably won't be able to save the drives myself - and any more advanced HDD recovery requires removing BIOS chips from the PCB boards and other stuff that I know I'm not capable of.

 

SO - I'm guessing I can send them off to someone who can recover the data. So I see the 3 following scenarios, which is the most realistic/practical?

 

A) Leave the server off until the data is recovered - if I do this and each drive has it's data moved to a new 4TB drive, can I implement the new drives without screwing up the array? I feel like that's where I do the New Profile configuration method.

 

B) I'm impatient and want to just keep using the server without the data from those drives while the data gets recovered - can a data recovery service take the data off a disk formatted for an unraid array, and deliver it to me in such a format that I can read through it, and select files to put back on to the server?

 

C) options I'm not considering? 

[JonathanM]

If you are willing to wait for a drive recovery service...

 

Send them all three drives, tell them they are members of a larger RAID pool and you only need one of the three, any one will do, but it must be bit perfect end to end, you can't use just the files if you only have one recovered.

 

IF they can't just revive 1 drive fully, or you don't want to wait and try to use the array to recover, then you can have them pull the files off all three and put the data back by copying it.

 

Once you do a new config and start using the array, you lose any chance of attempting recovery with any 1 of the three drives, you must have the file content of all three to get all your data back.

 

This would have been less painful if 2 out of the 3 were your 2 parity drives, as they don't have any files, so you would just need to recover the 1 data drive.

[gravyrobbers91]

1 hour ago, jonathanm said:

If you are willing to wait for a drive recovery service...

 

Send them all three drives, tell them they are members of a larger RAID pool and you only need one of the three, any one will do, but it must be bit perfect end to end, you can't use just the files if you only have one recovered.

 

IF they can't just revive 1 drive fully, or you don't want to wait and try to use the array to recover, then you can have them pull the files off all three and put the data back by copying it.

 

Once you do a new config and start using the array, you lose any chance of attempting recovery with any 1 of the three drives, you must have the file content of all three to get all your data back.

 

This would have been less painful if 2 out of the 3 were your 2 parity drives, as they don't have any files, so you would just need to recover the 1 data drive.

Welp I just called one data recovery service, who basically said the only way they can service, based on their business, is to have all 13 drives sent to them so they can assess on their grounds, and then send a firm quote, but that with their services it would be 9300-23000 dollars. lol. This is an entirely personal use system. So that's off the table.

 

Will keep searching, and hopefully find someone local (Boston) who can just examine the 3 drives, and either fix the single drive itself so I can do a rebuild, or copy all 3 drives onto 3 new drives, again for a rebuild.

[gravyrobbers91]

11 hours ago, itimpi said:

No - it is an all or nothing scenario.    A rebuild with 2 parity drives requires all except a max of 2 failed drives to be read reliably for the rebuild to work.   With 3 failed drives this is not possible.

 

 

Also when you say all or nothing, does that mean if i scrapped the drives and got 3 new ones, I couldn't run the array at all, like even without the data that was on those drives, and would have to erase the entire array. Or that I could indeed keep using the array, I just will have lost the data that was on those 3 drives

[itimpi]

To get the array back into operation without a rebuild you would need to use Tools->New Config to allow drives to be assigned and new parity built based on the assigned drives.    UnRaid will recognise array drives that are already set up with UnRaid partitioning and will add them into the array leaving their data intact.

[gravyrobbers91]

32 minutes ago, itimpi said:

To get the array back into operation without a rebuild you would need to use Tools->New Config to allow drives to be assigned and new parity built based on the assigned drives.    UnRaid will recognise array drives that are already set up with UnRaid partitioning and will add them into the array leaving their data intact.

 

Good to know. Honestly. 90% of the data on them is probably movies and music, and not even nearly the majority of it, so i think I'm just gonna eat the L. I got ahold of someone whose practice in data recovery is more catering to my needs, but even then i'm looking at $700 at the very least

Edited May 20, 2021 by gravyrobbers91

[itimpi]

18 minutes ago, gravyrobbers91 said:

 

Good to know. Honestly. 90% of the data on them is probably movies and music, and not even nearly the majority of it, so i think I'm just gonna eat the L. I got ahold of someone whose practice in data recovery is more catering to my needs, but even then i'm looking at $700 at the very least

 

If you make sure that you have a good backup strategy in place for anything that is important or irreplaceable then this is normally a sensible decision to take.

 

If you DO decide to go the data recovery route and but forgo any attempt to rebuild then you should mention that each disk is a self-contained file system.  It will probably be XFS unless you changed the default in Unraid to be something else.

 

[dschrade]

do you know if the drives was formatted at xfs or btrfs? I had a drive that unraid wouldnt let be mounted and was able to install xfs file system on my windows machine. then plug the drive into it to recover the files.