zpool list FREE vs zfs list AVAIL

[Eugene M. Zheganin]

Hi.

What is the difference between zpool list FREE for a pool and zfs list
AVAIL ? Because they differ a lot, I'm looking at a server at the moment
where the difference is like dozens of times: zfs list reports that 97
gigabytes is available, and the zpool list for the same pool says that
4.18 terabytes is free. From my point of view this should be the same
number.

Thanks.
Eugene.