Vultr has one of the better OpenBSD installations that I’ve seen and offers a level if trust I can appreciate. I’m sure there are some others like Amsterdam but I do not know anything about them as yet.

Per usual … create a block storage instance and an OpenBSD instance… in the same datacenter (NJ in my case)

• from the GUI attach the storage to the instance
• Probably not reuired but I rebooted my instance
• I had to look for the instance guessing it’s sd1… dmesg | grep sd1 (assuming sd0 is the instance drive)
• partition the disk fdisk -e sd1 … (cmd) reinit … (cmd) write
• format the partition… newfs sd1c
• get the disk id: sysctl hw.disknames
• add row to /etc/fstab … echo "706e5c5d280789f2.c /opt ffs rw 0 0" >> /etc/fstab or whatever you need
• mkdir a mount point… mkdir /opt
• manually mount the storage… mount /opt

That should do it.