Let me introduce myself on this cut.

[xtrap225]

evaluating freenas on my new used DS4246 connected to a lenovo with a lsi HBA in the 16x slot and 32GB of ram, and a gen 3 (i think) i5.

i was using and have 20 days left on my unRaid demo license and i couldn't resist popping over to freenas to properly check it out for myself, youtube just isn't cutting it.

i haven't used zfs since 2011 or so when my company setup a white boxed Nexenta, which went horribly wrong when the dude heading that project turned on dedup and then mucked things up and it took like 2 months to rebuild. at least that is the way i remember it.

 

[gpsguy]

Welcome to the forums!

We don't recommend dedupe on FreeNAS. The rule of thumb, if using it, is 5GB of RAM per 1TB of storage.

 

[jgreco]

i haven't used zfs since 2011 or so when my company setup a white boxed Nexenta, which went horribly wrong when the dude heading that project turned on dedup and then mucked things up and it took like 2 months to rebuild. at least that is the way i remember it.

It's REALLY funny because I was JUST visiting with someone who had a similar experience in a similar timeframe. Set up a fancy Nexenta system with lots of storage and two heads and it blew its brains out when he tried to do maintenance and failed over everything to the backup. Pretty sure the issue was not enough memory.

Do NOT use dedupe unless you plan to give it gobs of memory resources to work with, and are willing to keep an eye on it, and if you think you need dedupe on a critical-must-be-running box, really really maybe reconsider and just get yourself a whole bunch more disk space instead, and avoid dedupe.