TekWarfare Posted October 16, 2020 Share Posted October 16, 2020 I've got three WD 12TB disks: 2 data and 1 parity. I would like to stage a hard drive failure to test both the rebuild process and how well the information is restored. Is it possible to lose a parity disk and rebuild that? As far as I'm aware it would be one of the data disks I would have to wipe If anyone could guide me through the process of emulating a HDD failure I would be extremity grateful. Thanks in advance Quote Link to comment
itimpi Posted October 16, 2020 Share Posted October 16, 2020 You can simulate any disk failing by doing the following: stop array unassign the disk start the array to commit the change and make Unraid ‘forget’ the old assignment. If the disk was a data drive Unraid will show it as being emulated (i.e. its contents still available) using the combination of parity plus other data drives. If a parity drive then Unraid will now simply show the array as unprotected.. stop the array assign the disk to be rebuilt (data or parity it does not matter) start the array to commit the change and start the rebuild. 1 Quote Link to comment
TekWarfare Posted October 16, 2020 Author Share Posted October 16, 2020 (edited) Followed your advice and it's started the rebuild process. Easier than I thought it would be. Could I wipe the disk (in a Windows system) once I've unassigned it? The idea being that I'm 100% sure the data is gone and can fully evaluate the recovery process. Or, is this superfluous; does the rebuild process write at a sector level? Thank you very much for your help, itimpi 🙂 Edited October 16, 2020 by TekWarfare Quote Link to comment
itimpi Posted October 16, 2020 Share Posted October 16, 2020 That is up to you. The rebuild process involves re-writing every sector on the drive so in that sense it is superfluous. However you may want to prove this to yourself . 1 Quote Link to comment
TekWarfare Posted October 17, 2020 Author Share Posted October 17, 2020 So I made an attempt to do this before I followed your advice and it resulted with all my files being placed in a "lost+found" folder on the 'replacement' drive. I did have to run a file system repair with -l, -n and no switch as before that it was complaining of no file system. As this rebuild was meant to write on a per-sector level I assumed it would have restored data in its original form - how it was back when I did the parity sync. This hasn't been the case. I'm at a loss as to what it has actually been doing for the past day then. Is there a way to rebuild the array again so my files are in the correct location? Quote Link to comment
itimpi Posted October 17, 2020 Share Posted October 17, 2020 That should not happen as long as the following are true: Parity is valid before the rebuild the ‘emulated’ drive mounts with no problems and shows all your files Quote Link to comment
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