ZFS disk benchmark causes crash

[LnxBil]

So where actual shows what I can use?

There is no display for that in RAIDz*, it depends on the ashift, zvolblocksize, compressability and number drives in a vdev. As with a lot of CoW filesystem, you should not excees 80% usage due to performance and will not excees 93%, then is your pool full.

If you want better estimates for the size, just use stripped mirrors (raid10 and it is "see what you get" ) or don't use ZFS.

 

[Dunuin]

With 4 disk raidz1 you usually get ~40% of raw capacity as usable storage for VM virtual disks (already includes the 20
% that should be kept free), as everything written to a zvol will be 150% in size. You would need to increase the volblocksize to get some more usable storage with the downside of very bad performance for very small blocks.