After upgrading 11.0-RELEASE-p10 to 11.1-RELEASE I suddenly see a huge amount of kstat.zfs.misc.arcstats.l2_cksum_bad (nearly 2% of kstat.zfs.misc.arcstats.l2_hits). I have set > vfs.zfs.compressed_arc_enabled="0" in loader.conf. When removing this, the errors are gone. It seems that option is not working well in 11.1-RELEASE.