The capacity from output of zpool list have a huge difference with zfs list.

[guanfeix]

I build some thick-volume from one pool.But the capacity was far more beyond from my expectency.
I read the document of openzfs. Even though the method between the "zfs list" and "zpool list",likes slop space.But it doesn't fit to common sense. It really confussing me a lot.

[rincebrain]

zfs list will include things like if you have reservations that stop you from using that space for other things, like zvols default to being created with, or estimated space remaining after raidz overhead, while the "ALLOC" column of zpool list tells you how much space actually is allocated to data really written, would be my terse summary.

So in a simple example, if you have those zvols referencing, say, 750G each, but the volumes are sized 5.2T each, you'd end up with like 20.8T reserved and unavailable for anything else, but zpool list would say only 3T ALLOC.

[guanfeix]

tks, it' s quite clearly for me.