9.8.1 General information on I/O Throttling 9.8.2 I/O Throttling on front end I/O control 9.8.3 I/O Throttling on back-end I/O control This is a list of items to keep in mind when thinking about I/O Throttling: You can use throttling for a better front end I/O control, at volume, host, host cluster, and  offload levels: You can use this to allow restricted I/Os from a data mining server and a higher limit for an  application server. For example, a video streaming application can have a limit set to avoid consuming too  much of the bandwidth. For example, Department A gets more bandwidth than Department. For example, a backup volume can have less bandwidth than a production volume. [XCOPY/WRITESAME(VMware), ODX-WUT (HyperV)] can be confined by defined  controller resources. You can also use throttling to control the back-end I/O by throttling the storage pools, which  can be useful in the following scenarios: GLYPH<SM590000> IOPS and BW throttles limits can be set GLYPH<SM590000> Upper Bound QoS mechanism GLYPH<SM590000> No minimum performance guaranteed GLYPH<SM590000> Volumes, hosts, host clusters and managed disk groups can be throttled GLYPH<SM590000> Queuing at microsecond granularity GLYPH<SM590000> Internal I/Os are not throttled. (such as FlashCopy, cluster traffic, and so on) GLYPH<SM590000> Reduces I/O bursts and smoothens I/O flow with variable delay in throttled I/Os GLYPH<SM590000> Throttle limit is a per node value GLYPH<SM590000> In a multi tenant environment, hosts can have their own defined limits. GLYPH<SM590000> An aggressive host consuming bandwidth of the controller can be limited by a throttle. GLYPH<SM590000> Restrict a group of hosts by their throttles. GLYPH<SM590000> Each volume can have a throttle defined. GLYPH<SM590000> Offloaded I/Os. GLYPH<SM590000> Each storage pool can have a throttle defined. GLYPH<SM590000> Both parent and child pool throttles are supported (non DRP pools). GLYPH<SM590000> Allows control of back-end I/Os from the IBM FlashSystem 9100. GLYPH<SM590000> Useful to avoid overwhelming any external back-end storage. GLYPH<SM590000> Useful in case of VVOLS since a VVOL gets created in a child pool. A child pool  ( mdiskgrp ) throttle can control I/Os coming from that VVOL. At the time of writing child  pools only applies to standard pools and not DRP pools. GLYPH<SM590000> Parent and child pool throttles are independent of each other. A child pool can have higher  throttle limits than its parent pool (non-DRP pools). 350  IBM FlashSystem 9200 and 9100 Best Practices and Performance Guidelines