ZFS with Dedupe with 32GB RAM

[Nystral]

I've used FreeNAS and NAS4Free off and on for about 5 years now as both an ESX VM and main OS. I currently have an Ivy Bridge Core i5 with 32GB RAM on an ASROCK H77 Pro4/MVP and planning on purchasing 8 2TB NAS drives like the WD Red or Seagate NAS and creating a new RAIDZ2 pool for ~12TB useable.

I have a few questions though:
IF I turn on dedupe for this pool and migrate ~5TB of data over will the 32GB RAM be enough? I have maxed out the RAM on this mobo and the only other option would be to move to a server class mobo and processor which is a bigger investment then I'm comfortable with at the moment.

Would adding a cache SSD help with the dedupe? I've read that cache drives are "nice to have" but not worth it unless you fall into an edge case and I'm not sure I do.

Thanks for the help.

[b0ssman]

importing an unclean pool can require between 3-5 GB of RAM per TB of deduped data, and if the system doesn't have the needed RAM it will panic, with the only solution being to add more RAM or to recreate the pool. Think carefully before enabling dedup!

and the ssd wont help.

what exactly do you want to use dedupe for? in most scenarios this will not give you much more space and will cause you a lot of headache.