Looks like your drive is dying (if SSH) or having media errors (if HDD) or maybe controler or cable or other hardware error. Maybe replace the drive (and restore the VMs from backups)?
EDIT: You might not be able to read the data due to errors or it might be silently corrupted. I'm not sure if it is worth the trouble, if the data is not important since you don't have backups.
Looks like your drive is dying (if SSH) or having media errors (if HDD) or maybe controler or cable or other hardware error. Maybe replace the drive (and restore the VMs from backups)?