You can set the maximum amount of I/O activity that a host sends to a volume. This amount is known as the I/O governing rate. The governing rate can be expressed in I/Os per second or MB per second.
Read, write, and verify commands that access the physical medium are subject to I/O governing. I/O governing limits the amount of I/O that the system allows to a particular volume. The system allows operations without slowing down the I/O until the I/O governing limit is reached, then no further I/O is allowed until the next governing period (1 second).
I/O governing does not affect FlashCopy and data migration I/O rates.
I/O governing on a Metro Mirror and Global Mirror secondary volume does not affect the rate of data copy from the primary volume.
Refer to Configuring a balanced storage system for a description of the steps for setting up I/O governing.