Run 'zpool import' to list which pool cannot be imported:
# zpool import
status: One or more devices are missing from the system.
action: The pool cannot be imported. Attach the missing
devices and try again.
test FAULTED missing device
Additional devices are known to be part of this pool, though their
exact configuration cannot be determined.
ZFS attempts to store enough configuration data on the devices such
that the configuration is recoverable from any subset of devices. In some
cases, particularly when an entire toplevel virtual device is not attached to
the system, ZFS will be unable to determine the complete configuration. It will
always detect that these devices are missing, even if it cannot identify all of
The pool cannot be imported until the unknown missing device is
attached to the system. If the device has been made available in an alternate
location, use the '-d' option to 'zpool import' to search for devices in a
different directory. If the missing device is unavailable, then the pool cannot