Hello. I have 8 disk UnRaid system. 2 parity drives and 6 data. Due to water damage 1 parity and 2 data drives has failed. I've try to clean and dry them up but no luck. I already ordered new drives. Is there any chance to recover lost data?

If the water damaged disks are able to power up you might be able to use UFS Explorer to see/recover data if possible. The free trial should let you at least see what's potentially on the disks.

However without having both parity disks, you have too many failed data disks for parity to function at this point.

How long have you let them dry?

About a week

Thanks MowMdown. Would UFS Explorer be able to recover parity drive?

46 minutes ago, banaswork said:

Thanks MowMdown. Would UFS Explorer be able to recover parity drive?

No. The parity drive does not have a file system to be recovered.

Would I be able to recover at least 1 data drive since I still have 1 parity drive working?

Parity by itself can rebuild nothing. Parity plus all other disks are read to get the calculated data to write to the rebuilding disk. Since there was dual parity, 2 disks could be recovered, but with 3 missing, there is no way to calculate the data for any disk.

Parity is very simple, and it is basically the same concept wherever it is used and however it is implemented. Parity is just an extra bit that allows a missing bit to be calculated from all the other bits.

If you are interested, go to this link:

https://docs.unraid.net/unraid-os/getting-started/what-is-unraid/

then expand the Software-defined NAS section, then expand the How Parity Works section.

4 minutes ago, trurl said:

How Parity Works

Parity2 calculation is actually more complicated than that, but it is still just an extra bit that allows a missing bit to be calculated from all the other bits.

Thank you for everyone's help. Hopefully I can find most of my data on other disks and better protect server from water damage. I guess not allowing wife to server room should work. 😜