How to reduce Proxmox VE guest machine backup size
To reduce a guest machine before you perform a backup, first set the discard flag on the guest machine (while turned off), then do a TRIM inside the machine.
Run this command inside the guest machine (assuming it's running Linux): fstrim -a -v
What it does is it emulates SSD TRIM facility, which blanks out free space, since deleting a file only removes a file but doesn't mark the space as free.
Category:
System Administration