https://www.theregister.co.uk/2018/01/17/zfs_performance_hit_by_spectre_meltdown_bug_fixes/ >The widely used ZFS file system software is slowed down in both read IOPS and throughput by fixes for the Spectre and Meltdown bugs. >Systems engineer Jon Kensy blogged about the results of his ZFS testing, based on a VM running ZFS on a Ubuntu 16.04 LTS system on a Dell R620.