Listing Pool-Wide I/O Statistics

When issued 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        alloc   free   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
rpool       6.05G  61.9G      0      0    786    107
system1     31.3G  36.7G      4      1   296K  86.1K
----------  -----  -----  -----  -----  -----  -----

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 system1 2
capacity     operations    bandwidth
pool           alloc   free   read  write   read  write
----------     -----   -----  ----  -----  -----  -----
system1        18.5G  49.5G      0    187      0  23.3M
system1        18.5G  49.5G      0    464      0  57.7M
system1        18.5G  49.5G      0    457      0  56.6M
system1        18.8G  49.2G      0    435      0  51.3M

In this example, the command displays usage statistics for the pool system1 every two seconds until you press Control-C. Alternately, you can specify an additional count argument, 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.