Zpool made of ZVOLs?

[Kimmo Paasiala]

Is it possible and even recommended to create a zpool out of block
devices that are actually ZVOLs?

I'd like to have a separate zfs pool for poudriere because building
ports with it disrupts the snapshotting on my main pool if the
poudirere jails are created on it. At the same time I don't want to
resort to using external disks to create a pool that is only used for
a jail or two.

Regards,

-Kimmo