ZFS and block device replication

[Mister Olli]

Hi,

I'm starting digging into FreeBSD and ZFS and came up with a question
which is bothering me.

I'm thinking about placing block device replication (e.g. via DRDB or
NDB) under a ZFS/ ZVOL. It would improve replication as it's done
immediately, not within a time-frame (as the 'zfs [send/receive]'
approach would.

Imagine I have an active/ passive setup. would all the ZFS volumes and
ZVOLs be available on the passive node, even if I haven't configured
them explicitly?

Regards,
---
Mr. Olli