encrypted ZFS - pros and cons for two approaches?

[geos]

I use dm-crypt'ed devices and build ZFS array on top of them. how does it compare to quite opposite approach: creating ZFS, creating ZVOL out of it and then encrypt ZVOL with dm-crypt? are there any pros or cons for each approach?

one thing that comes to my head is that using ZFS over dm-crypt one needs to open few dm-crypt mapper devices separately first and CPU has more work to do while doing multiple encryption. for dm-crypt over ZFS I guess that it would require only one dm-crypt mapper device being open for ZVOL so that CPU would have less work while doing encryption. any others?

I would appreciate you opinion on pros and cons and thoughts from own experience on the subject.

thank you,
geos

[b0ssman]

nas4free uses geli not dm-crypt.