fixed vm storage (zfs, lvm)

How I can allocate fixed space for VM storage (virtual disk) on ZFS, LVM, and how to change it on working machine?
what do you mean? non sparse disks (iow no thin provisioning?)
if yes, on the zfs storage you need to uncheck 'thin provisioning'
and lvm is always not thin provisioned (lvmthin is always thin provisioned an this cannot be changed)
 
yes if you use a non thin provisioned storage (like LVM or zfs with 'thin provision' unchecked')