This attribute reports the disk bandwidth consumed by the ZPOOL for all read operations during the last interval.
The storage pool, ZPOOL, is a collection of virtual devices providing physical storage. Therefore, it is important to monitor input-output (I/O) statistics of the storage devices. As a ZPOOL is collection of various devices, the ZPOOL provides the collective I/O statistics at the storage pool level. Thus, ZPOOLs act more like physical disks rather than file-systems. There are various I/O statistics that are available at the ZPOOL level.
The value that is reported by this parameter is the total number of read operations for all the physical devices that are part of the ZPOOL.