My disk 2 has been failing and finally shot craps Saturday.  I had a new drive I had purchased to replace it and did the swap.  Started the server back up and added the new drive to disk 2.  The server did a parity/re-build for the last 20 hours.  However, disk 2 still shows unmountable and I can't access it even though the system says it's ready and under normal operation.  WTF is going on?

Put the array into Maintenance mode and run a file system check/repair on the drive.

 

it is worth pointing out that if a drive was showing as being emulated and as ‘unmountable’ before starting the rebuild then it will also show that state at the end.    It is quite likely that at the point the disk failed some minor file system damage occurred and parity is reflecting this.     The rebuild process is not aware of the data on the drive being rebuilt - it just works at the raw disk level making the physical drive match the emulated drive.

 

4 minutes ago, itimpi said:

Put the array into Maintenance mode and run a file system check/repair on the drive.

 

it is worth pointing out that if a drive was showing as being emulated and as ‘unmountable’ before starting the rebuild then it will also show that state at the end.    It is quite likely that at the point the disk failed some minor file system damage occurred and parity is reflecting this.     The rebuild process is not aware of the data on the drive being rebuilt - it just works at the raw disk level making the physical drive match the emulated drive.

 

The original disk 2 that had all my data on it that failed went into this "unmountable" mode.  I tried several things to get it to mount and work but no go.  I knew the drive was starting to fail so I assumed it finally had done so.  I replaced the drive and started the server with the new hard disk and added it to the disc 2.  The new drive also showed unmountable at the beginning of the parity/re-build as it currently does in the screen shot.  So that brings me to this as now I'm scared of losing my TB's worth of data that was on that original disk 2.  Should I do the file system check/repair on the brand new drive that is currently installed or on the one that was failing?

Here is what running the file system thing says on the new drive.  Don't really understand what any of this means.

That looks good as no significant corruption is being reported.    You now want to run with the -n option removed to run a repair rather than a simple check, and if asked for (which is expected) add the -L option.   Despite the scary sounding warning message it virtually never causes any data loss, and if it does it just relates to the file being written at the point of failure.    After that repair run completes you stop the array and restart in normal mode and now the drive should mount and show all your data intact.

 

BTW:   Do you have backups of any critical data?     You should never rely on the Unraid protection capabilities against disk failure as your only backup strategy as you can lose data in many more ways than hardware failure.

1 hour ago, itimpi said:

That looks good as no significant corruption is being reported.    You now want to run with the -n option removed to run a repair rather than a simple check, and if asked for (which is expected) add the -L option.   Despite the scary sounding warning message it virtually never causes any data loss, and if it does it just relates to the file being written at the point of failure.    After that repair run completes you stop the array and restart in normal mode and now the drive should mount and show all your data intact.

 

BTW:   Do you have backups of any critical data?     You should never rely on the Unraid protection capabilities against disk failure as your only backup strategy as you can lose data in many more ways than hardware failure.

I have done this with the new hard drive and started the array in normal mode.  It is now doing another parity/data rebuild when I started the array.  It does however appear to show the free & allocated size of disk 2 when before it showed unmountable during this process.  I'm assuming that after the sync/rebuild I should be good to go?  This will take about 21 hours based upon the one that ran yesterday and today.

Oh and also to answer your other question, No I don't have any other backup of this data.  Considering it's almost 34 TB.  I mean it's nothing I can't live without, I just would "prefer" not too considering the amount of time to get all this data back.

This worked, Back to normal operation.  Thanks