Matt Hamilton. An Internet technologist, interested in Python web development, iOS deployment and testing, wearables, networking and operating systems.
30 August 2015
I am using bhyve as a VM system for OpenBSD, Linux and FreeBSD guests running on a FreeBSD host.
I wanted to create a new OpenBSD VM to set up a local mail server VM. And realised I could probably clone one of my existing OpenBSD VM's filesystem and just start with that. I'm using ZFS zvols for the underlying data store for the VM.
So, firstly I took a snapshot of the running OpenBSD VM:
zfs snapshot storage/vms/openbsd@booted
Then clone it:
zfs clone -p storage/vms/openbsd@booted storage/vms/mailserver
Listing the zvols you can see the new one:
root@jenna:/storage/vms # zfs list -r storage/vms
NAME USED AVAIL REFER MOUNTPOINT
storage/vms 111G 4.82T 4.54G /storage/vms
storage/vms/mailserver 1.93M 4.82T 2.92G -
storage/vms/openbsd 106G 4.92T 2.92G -
What is interesting is the amount of storage used, in this case just 1.93M, so the new OpenBSD server seems to only consume space where different to the existing one. ZFS' copy on write is pretty awesome :)
in blog · Sun 30 August 2015