Start Systemd Service After Device Appears

What if you install a service on a volume group located on a separate disk that is not necessarily mounted at boot?

• Create fstab entries with nofail option

/dev/dbvg/db2mspr      /home/db2mspr         xfs       nofail                   0  0

• Create UDEV rule to activate the vg and mount the fs once the device appears

KERNEL=="devNameHere", RUN+="/bin/bash -c '/sbin/pvscan --cache -a ay && mount -a -O nofail'"

• Add a require directive for the mount point to the service file

[Unit]
RequiresMountsFor=/home/db2mspr
...