There is storage Dell MD3600f. It created thin 12TB volume. On the target machine, the volume mounted as the drive for the Proxmox path. Here is the problem. If the volume began to approach the end part of the data was moved to another location (copied via NFS from the path, then OS via the same new path and arrived data). The system began to write, freely 8TB. In fact, the place soon came to an end (according to the data from the storage interface itself), to record anything. Accordingly, the question is how to free up space, the data from which, as it was removed.
I tried to do so:
on the Proxmox server is connected to storage mounted
mount-t ext4-o discard /dev/vg-name/vm-xxx-disk-1 /mnt/mnt-name/
mount-t ext4 -o discard /dev/mapper/vg--vm--name--xxx--disk--1 /mnt/mnt-name/
or via fstab:
/dev/mapper/vg--name-vm--xxx--disk--1 /mnt/mnt-name ext4 defaults,noatime,discard 0 1
(tried this way and that)
Trying to do fstrim:
# fstrim /mnt/mnt-name
fstrim: /mnt/mnt-name: the discard operation is not supported
What am I doing wrong? How to "return" the free space? Remove a volume from the storage system interface, of course, possible, but I would like to understand how to free up space without losing the ENTIRE volume.