Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have FreeBSD 8.2 installed on AMD/64 with 3 GB RAM and 690 GB pooled HD under ZFS. I have two copies of an identical file (180 MB video) in same directory and yet df -h indicates that both are using storage. I thought de-dupe was "built-in" with ZFS. Have I configured something wrong?

share|improve this question
up vote 2 down vote accepted

FreeBSD 8.2 only supports ZFS v15, but dedupe requires at least v21. Link

I think that dedupe is coming with FreeBSD 8.3.

Other considerations:

  • Depending on your pool setup, dedupe doesn't necessarily happen in real time.
share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.