I had a drive go bad over the weekend so i replaced it yesterday and ran a data rebuild on it. It just finished and it did not rebuild all of the data that was on the original 4TB drive. The original drive had about ~60GB free, the new drive after rebuild is empty. I have attached diagnostics and a syslog.

 

storage-diagnostics-20160426-1606.zip

storage-syslog-20160426-1606.zip

Did you happen to press format at any point in the procedure?

I don't believe so, i added the drive and then started the array

Looks like the drive was formatted around Apr 25 21:13:15.

I did have the array running in maintenance mode last night for a short while, i feel like when it was in maintenance mode that it maybe started doing a rebuild and i cancelled it, i dont remember clicking format after that but obviously i did. I take it that for the most part ive just lost 4TB worth of data then haven't i?

I did have the array running in maintenance mode last night for a short while, i feel like when it was in maintenance mode that it maybe started doing a rebuild and i cancelled it, i dont remember clicking format after that but obviously i did. I take it that for the most part ive just lost 4TB worth of data then haven't i?

 

If you formatted, pretty much zero chance of recovery.

 

I'd suggest trying to recover data from the "bad" drive. In most cases you can still pull the data off of a bad drive unless it was a complete failure.

I did have the array running in maintenance mode last night for a short while, i feel like when it was in maintenance mode that it maybe started doing a rebuild and i cancelled it, i dont remember clicking format after that but obviously i did. I take it that for the most part ive just lost 4TB worth of data then haven't i?

If you're uncertain, either about what you are doing, or about what unRAID is doing, come to the forum and ask before you make a big mistake.