I did a brief write-up about this effect on the ZoL issue tracker: https://github.com/zfsonlinux/zfs/issues/4785#issuecomment-228072722 https://github.com/zfso

I did a brief write-up about this effect on the ZoL issue tracker: https://github.com/zfsonlinux/zfs/issues/4785#issuecomment-228072722 https://github.com/zfsonlinux/zfs/issues/4785#issuecomment-2... In short, if you want more consistent performance as the pool fills, disable metaslab_lba_weighting_enabled, but be prepared to lose some sequential performance when the pool is empty.