The easiest way to determine if any known problems exist on a system is to use the zpool status –x command. This command describes only pools that are exhibiting problems. If no unhealthy pools exist on the system, then the command displays the following:
# zpool status -x all pools are healthy
Without the –x flag, the command displays the complete status for all pools (or the requested pool, if specified on the command line), even if the pools are otherwise healthy.
For more information about command-line options to the zpool status command, see Querying ZFS Storage Pool Status.