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.