This tool displays ZFS pool latency histogram in a way that should
be more intuitive than the numbers output by "zpool iostat -r".

Letters from "." over "a" to "z" and finally "^" are displayed for
higher numbers of latencies observed either over the run-time of
the program or within each 3 second interval.

WWW: https://github.com/chadmiller/zpool-iostat-viz