eg：
hbwosseniq(root) #: zpool status -v
pool: eniq_sp_1
state: ONLINE
status: The pool is formatted using an older on-disk format. The pool can
still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'. Once this is done, the
pool will no longer be accessible on older software versions.
scrub: resilver completed after 0h0m with 0 errors on Fri Jul 16 11:36:33 2010
config: