In the light of adminX’s answer I decided to format my whole disk to ext4 and mount it to /srv. I tried to make the mount permanent following this article in the OpenWRT wiki. Thus I ended up with this in /etc/config/fstab:
config ‘global’
option anon_swap ‘0’
option anon_mount ‘0’
option auto_swap ‘1’
option auto_mount ‘1’
option delay_root ‘5’
option check_fs ‘0’
config ‘mount’
option target ‘/srv’
option uuid ‘xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxx’
option enabled ‘1’
Is this the correct way to go?
TIA & Best regards
Peter