3 ms·

I'm curious about dedup being a four letter word in a number of ZFS circles. I hadn't seen anything bad about it (other than it being heavy on ram and possibly

• rincebrain 10y ago
  So, dedup has a nontrivial memory overhead, can't really be turned off short of recreating the datasets in the pool after it's turned on (ZFS doesn't have any operations that allow you to change data blocks retroactively, so setting a new compression type, or checksum...or dedup entry for a block can't be changed back without you copying the data after changing the setting), and can have a significant write performance impact depending on your setup. See [1] for an example of how bad this can be. A number of people run dedup in production workloads. You just need to understand that it's a big and weirdly-shaped hammer, and can hit you in the head if you swing it without being ready for it. [1] - https://forums.freebsd.org/threads/31184/ https://forums.freebsd.org/threads/31184/