Listing Pool-Wide Statistics

With no options, the zpool iostat command displays the accumulated statistics since boot for all pools on the system. For example:

# zpool iostat
               capacity     operations    bandwidth
pool         used  avail   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
tank         100G  20.0G   1.2M   102K   1.2M  3.45K
dozer       12.3G  67.7G   132K  15.2K  32.1K  1.20K

Because these statistics are cumulative since boot, bandwidth might appear low if the pool is relatively idle. You can request a more accurate view of current bandwidth usage by specifying an interval. For example:

# zpool iostat tank 2
               capacity     operations    bandwidth
pool         used  avail   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
tank         100G  20.0G   1.2M   102K   1.2M  3.45K
tank         100G  20.0G    134      0  1.34K      0
tank         100G  20.0G     94    342  1.06K   4.1M

In this example, the command displays usage statistics only for the pool tank every two seconds until you type Ctrl-C. Alternately, you can specify an additional count parameter, which causes the command to terminate after the specified number of iterations. For example, zpool iostat 2 3 would print a summary every two seconds for three iterations, for a total of six seconds. If there is a single pool, then the statistics are displayed on consecutive lines. If more than one pool exists, then an additional dashed line delineates each iteration to provide visual separation.