So the node was running for like couple of years. Last two months time to time it was crashing, but that’s because of SMR drive and high iowait, was about to move it to CMR, but…
After last crash, HDD become empty. Have no idea how? Except that, it’s UUID - changed 
(different that before it’s does not mount unless i change fstab). Everything was running on RPi. e2fsck - never find any problems on this drive.
Is there anything you could recommend me? Is there something like “Undelete” or “Unformat” under the Linux for ext4?
ty