PSA: ZFS performance bug on >=256k recordsize

[snullp]

I have been seeing this issue for years and recently I finally figured it out: https://github.com/openzfs/zfs/issues/18893
Before this bug is fixed do not use recordsize that is >= 256k.

 

[snullp]

If your system have lots of free RAM, but: 1. swap is full, 2. ARC lower than your expectation and 3. have an active dataset with >=256k recordsize. You might be affected by this bug.
You can try stop the workload on the dataset to see if situation improves.