Volume for iSCSI problem

[is99]

I'm trying to connect to FREENAS box using iSCSI

First I created a ZFS volume from all my disks, so now under "Storage-Volumes" I see /mnt/Data and its size is 2.6 TiB
So far so good

Now as far as I understand in order to use it for iSCSI I need to go to this volume and "Create ZFS Volume" when I press it no matter what I write I always get "cannot create 'Data/data': volume size must be a multiple of volume block size"

How can I just use all my /mnt/Data for this volume ?

 

[pete_c20]

I think this means that the 'ZFS volume size' should be a multiple of the hard disks you've used to set the volume up with. I think I have a very similar situation to yourself, so to use that as an example -
After volume creation I have 2.6TBytes space. This is made from 8 x 500GB drives in a RAIDZ2.
To still keep the benefits of ZFS (after all it's the only reason as to why I've even touched FreeNAS, because I want scrub and some form of a reliable maintainable storage system) I've created a ZFS Volume to use with iSCSI. For now I've given up trying to setup CIFS and rsync.
Some ZFS Volume size settings that work for me are:
2.5T (ie 5x the HDD size), or it can be type in as 2560G.
2.0T (ie 4x the HDD size) also works but it's getting a bit low, as I need at least 2TB space.
Now my other concern is the wish to leave some free space on the volume/ZFS volume so that if it ever became full then it can be sorted out and files deleted. A couple of times I've read that completely filling a ZFS volume is a bad idea, and that as a rule of thumb the volume should only fill 80% of the available space. But as to exactly where to build in the space I'm not sure.