I wouldn't recommend continuing to work with the sda disk.
It already showed irreparable read errors. Very bad sign.
At least check the smart data of the disk (smartmontools). to see te
overall health of the disk.
Usually it already had several read errors/bad blocks that the operating
system didnt see due to self healing mechanisms (block relocation).
That would mean it will very likely fail again soon. If that read error
from your logs was on new peronal data you dont have on a backup then
you already have irreversible data loss. You dont want to have that
I would get me a new disk, restore a recent backup of sda on it (or
install os from scratch) and then try to salvage any important data from
sda that was not on the backup by simple file copy (with the old sda
The details of this vary depending on the exact setup (LVM used? 3 disks
directly attachable at the device or the Ubuntu server, ...) or personal