Splitting disk into more partitions

[Peter Flynn]

When setting up a particular machine, I thoughtlessly allowed the system
to use the whole disk as a single user partition, so it created

/dev/sda1	fat32	/boot/efi	512 MiB
/dev/sda2	extended		1.82 TiB
.../dev/sda5	ext4	/		1.82 TiB

This works fine, but /home and /var/lib/svn should really have been
separate partitions because they will grow while the rest will be fairly
static. There is 1.63 TiB unused space on /dev/sda5.

I seem to remember having to do this once before, but things would have
changed since ext2 days. I know it was possible on Windows systems, to
create a new partition in unused space, where Linux could be installed
to make it dual boot.

I would aim to resize sda5, and then create two new partitions in the
unused space. Then I can copy the needed data into the new partitions,
reboot to single-user mode, edit /etc/fstab and reboot. Before I try to
do anything in gparted, does anyone have any warnings? (Like "Don't")

It's all backed up, so while I'd rather not screw it up, it's not a
disaster if I do.

(And I can't find anything in the Subversion docs about this specific
request: I know trying to move repos to different physical disks will
fail, for very sensible security reasons, but I have no idea if
relocating the repos on the same spindle will also fail.)

Peter