Using Files
To use files on an existing filesystem, create four 128 MB files, eg.:
# mkfile 128m /home/ocean/disk1
# mkfile 128m /home/ocean/disk2
# mkfile 128m /home/ocean/disk3
# mkfile 128m /home/ocean/disk4
# ls -lh /home/ocean
total 1049152
-rw------T 1 root root 128M Mar 7 19:48 disk1
-rw------T 1 root root 128M Mar 7 19:48 disk2
-rw------T 1 root root 128M Mar 7 19:48 disk3
-rw------T 1 root root 128M Mar 7 19:48 disk4
This is easy for testing you don't need real disks or partitions
(source: http://flux.org.uk/howto/solaris/zfs_tutorial_01)