I've got 2 volumes already mounted on a VPS from Hetzner.
The first one is on / with 1To space. The other one on /home with 2To space.
I want to get my 3 To together, how can I manage to merge those 2 volumes without erasing any data ?
Here is a picture of what a df -h looks like :
Thanks you very much !
You can merge them using a union filesystem. https://en.wikipedia.org/wiki/UnionFS
In Linux, you can find several kernel modules implementing a union fileystem such as aufs and overlayfs. Available modules may vary depending on kernel configuration in your vps. I will give you a configuration example using the aufs kernel module.
In first, create a subdirectory for each mount point:
mkdir -p /for-aufs
mkdir -p /home/for-aufs
To continue, create a directory for the aufs mount point:
mkdir -p /aufs
Edit your /etc/fstab file
none /aufs aufs br:/for-aufs=rw:/home/for-aufs=rw,sum,create=rr 0 0
Or using mount directly:
mount -t aufs -o br:/for-aufs=rw:/home/for-aufs=rw,sum,create=rr none /aufs
Then, you will see a new mount point in /aufs linked to /for-aufs (/dev/md2) and /home/for-aufs (/dev/md3) when executing df -h. When you are using /aufs mount point, a round-robing policy will create/modify files between /for-aufs and /home/for-aufs.
In conclusion, /for-aufs + /home/for-aufs = /aufs
Remember to read the manual for more information: http://manpages.ubuntu.com/manpages/focal/man5/aufs.5.html