[6.12.2] zfs write speed very slow (e.g. ~ 30MB/S)

There's a known issue with zfs write speed on the array, but moving data from disk to disk with parity as you are doing will always be quite slow, even when using a different filesystem it won't be much faster, usually tops at around 60MB/s.

If it just would be 50-60MB/s ...  Will do a test later and move files to the remaining btrfs drive to cross-check 

2 minutes ago, hulk66 said:

If it just would be 50-60MB/s .

Yes, that should be about array to array write speed with btrfs/xfs, like mentioned with zfs write speed will be slower until that issue is fixed.

 

ok, thank you! Do you know if there any such thing as a ticket or so, which one could follow for his matter?

You can follow the bug report I linked above, when there's more info or it's fixed I'll post there.