Some data missing after recovery

Hi first my system

 

4x 4tb Disk

1 x parity and 3x data

unraid 6.1.9

 

2days i lost a disk and replaced it last night, and it ran a recovery and

it took about 6hours, and i wrote it was rebuilding my disk,

this morning some of the data folders are still empty, what have i done wrong?

and are those things lost? then what is the point with raid?

Hi first my system

 

4x 4tb Disk

1 x parity and 3x data

unraid 6.1.9

 

2days i lost a disk and replaced it last night, and it ran a recovery and

it took about 6hours, and i wrote it was rebuilding my disk,

this morning some of the data folders are still empty, what have i done wrong?

and are those things lost? then what is the point with raid?

 

Not clear what you have done. I'm guessing someone probably will ask for logs + screenshot of your array config.

 

Very first question: what do you mean by "data folders are still empty"?

Logs comes AS soon AS i get home in a hour

By folder i mean like /mnt/user/somefolder

The folder is there but its empy

Heres the "new" array

 

https://gyazo.com/c50bf419469aba177e4c710fb1c4e2c6

where disk 1 (sdd) is the one i replace with the old 2TB

 

and the log for 2 days

 

http://pastebin.com/2bFYRwLi

and i follow this guide

https://lime-technology.com/wiki/index.php/Replacing_a_Data_Drive

Heres the "new" array

 

https://gyazo.com/c50bf419469aba177e4c710fb1c4e2c6

where disk 1 (sdd) is the one i replace with the old 2TB

 

and the log for 2 days

 

http://pastebin.com/2bFYRwLi

and i follow this guide

https://lime-technology.com/wiki/index.php/Replacing_a_Data_Drive

 

Looks like Disk 1 was formatted (mkfs.xfs on Jun 15 10:36:56), i.e. an empty file system written. Pretty sure that was not part of the guide...

yes, it said i couldt be mounted, but it was a new disk, so how

can that effect the array ? should i have been rebuild?

yes, it said i couldt be mounted, but it was a new disk, so how

can that effect the array ? should i have been rebuild?

 

Is this the sequence of event?

• 2TB drive fails and shows up as unmountable
  
• Replace 2TB drives with 4TB drives and rebuild
  
• 4TB drive still shows as unmountable after rebuild
  
• You format the 4TB drive
  
• 4TB is mounted but with empty share folder
  

Correct 

shall i run a parity check didnt try that

shall i run a parity check didnt try that

 

DO NOT RUN PARITY CHECK!

 

 

Parity check won't solve anything.

 

There are two things you can try to recover your data, copy it from the old disk if it's still readable or run xfs_repair on the rebuilt disk, this last option would have much better chance of success if you hadn't formatted the disk.

hm think the old disk i brokken , but give it a try ,

but how to i run xfs_repair

ok the old disk still have a bit life, so im gonna copy the missing data,

But if shall change disk another time, what is the best practices

Long explanation - pardon my previous post in red. Hope I wasn't too late.

 

Rebuilding an unmountable drive will result in another unmountable drive.

Being unmountable suggests it is already corrupted (file system?).

The rebuilding process simply re-create the drive as per what parity "remembers" and if parity remembers it as unmountable, it will return to that state.

 

Parity check in itself does no harm.

However, some might tick the "Correct any Parity-Check errors by writing the Parity disk with corrected parity." box.

That basically tells the parity drive to re-remember your now-formatted disk as being empty.

That results in zero chance of restoring any data as any parity info is lost.

 

What I would do (DO NOT do it yet, wait for an expert to 2nd it, or give another suggestion - I'm just another user so I do make mistakes too).

• Rebuild the 4TB again
  
• Run xfs_repair as per johnnie.black's suggestion
  

 

If you have already done a correcting parity check then I'm afraid your only recourse is to try to fix the original 2TB drive and recover as much data from it as possible.

 

 

well the old 2tb is a of this time readable still, so im coping my a.. of

but if i ever need to change a disk, and if its crashed, should raid still be able

to recover it ?

• Rebuild the 4TB again

 

Rebuilding again won't work since parity was updated during the format.

 

Your best bet is copying data from the old disk as I doubt xfs_repair will find any data, if it was reiserfs there would be better chances.

 

Mount the old disk with unassigned devices, or use your cache slot if available.

well the old 2tb is a of this time readable still, so im coping my a.. of

but if i ever need to change a disk, and if its crashed, should raid still be able

to recover it ?

 

What you did (except the format) is usually enough to recover from a disk failure, but if the disk is unmountable it should never be formatted, usually a file system check will solve the issue.

• Rebuild the 4TB again

 

Rebuilding again won't work since parity was updated during the format.

 

Yeah, that's what I suspected too so that's why told him not to do it until an expert confirms. Sounds like the 2TB is the only way to recover anything now.

 

I wonder if there's anyway to add a red note to users before the click the "Format" button. This is the 3rd times I remember seeing a post about this and I haven't been an active member for long.

 

Something like "Do NOT format if disk is still unmountable after a rebuild - ask the forum for further actions" would suffice I guess.

i may have missed something here there,

touch with a parity disk, that i could recover a lost disk,

but if the disk is broken, then i can't recover with a new one ?

then what is the point with parity ?

Parity will recover a dead drive.  However when you clicked format, you formatted the "emulated" drive which in turn meant that after the rebuild all the data was gone.

 

Sent from my LG-D852 using Tapatalk

 

 

so if i need someday to replace a deaddrive, i just jank out the old one, put in the new one

and let it rebuild?

well the old 2tb is a of this time readable still, so im coping my a.. of

but if i ever need to change a disk, and if its crashed, should raid still be able

to recover it ?

You could almost certainly of recovered all (or virtually all) of the data off the rebuilt disk if you had NOT told unRAID to format it.    The unmountable state often means that there is corruption at the file system level and the way to recover that is to put the array into Maintenance mode, click on the drive in question and use the option to check/repair the file system.

 

Points to take away:

• If a disk is 'unmountable' before you start a rebuild it will still be 'unmountable' when the rebuild finishes.  The rebuild does not fix file system level errors - it merely recovers from a faileded disk drive.
  
• Using the 'Format' option in unRAID is an instruction to write an EMPTY file system to the disk in question (i.e. throw away any data it currently contains).    It is never part of a recovery process.
  
• The fact that a disk drive is marked as 'disabled' in unRAID does not necessarily means that the drive has failed.  It merely means that a write to it failed so unRAID will stop using it until the issue is resolved.  Although the failed write can be due to a drive failing it can also be due to external factors such as bad connections, power fluctuations etc.  Posting the system Diagnostics (which contain syslog, configuration info, SMART reports etc) covering the failure period can help others give guidance on what has actually happened. and the best way forward.