On 9/2/25 06:05, Dan Ritter wrote:
David Christensen wrote:
a. Set the ZFS backup file system property "dedup". This will enable
block-level de-duplication, which can de-duplicate data more than hard links
alone.
This is generally not a good thing to recommend; one of the
authors of the system wrote a good article which should
definitely be read before turning on dedup:
https://despairlabs.com/blog/posts/2024-10-27-openzfs-dedup-is-good-dont-use-it/
-dsr-
Thank you for pointing out the article.
AIUI the thesis of the article is that "dedup is worse than useless on
general purpose workloads" [section "Unique Entries", paragraph two].
It would be interesting to know the OpenZFS developers' opinion of dedup
for backup workloads, including special vdev class vs. dedup vdev class.
https://openzfs.github.io/openzfs-docs/man/v2.3/7/zpoolconcepts.7.html
David
