And a non-cross posted post, mostly for my own memory.

ZFS uses the zpool command to create and manage the various filesystem pools.

zpool create mypool -f raidz1 /dev/sdb /dev/sdc /dev/sdd /dev/sde

This creates a pool named 'mypool' out of 4 virtual disks on the VM. The -f is to force the build, I'm not sure if this is needed because the disks are virtual.

zfs list shows the details of the pool or pools.

To allow a pool to be expanded (add additional drives), you set it with 'autoexpand=on'

zpool set autoexpand=on mypool

To add an additional disk to the pool, you just use the 'add' command with zpool.

zpool add -f mypool /dev/sdf

Pretty simple, I'll post more as I experiment with ZFS.