Draft Document for Review February 7, 2020 3:15 pm 8464ch09_Oper.fm Figure 9-32 The Host Throughput page  Cache throttling This window shows the statistics of the throttling values that are applied on the host write  operations and RUN copy operations throughout the grid.  Throttling  refers to the intentional slowing of data movement to balance or prioritize system  resources in a busy TS7700. Throttling can be applied to host write and inbound copy  operations. Throttling of host write and inbound copy operations limits the amount of data  movement into a cluster. Throttling is typically done for one of the following reasons: GLYPH<SM590000> The amount of unused cache space is low. GLYPH<SM590000> The amount of data in cache that is queued for premigration exceeded a threshold. Host write operations can also be throttled when RUN copies are being used and it is  determined that a throttle is needed to prevent pending RUN copies from changing to the  immediate-deferred state. A throttle can be applied to a host write operation for the following  reasons: GLYPH<SM590000> The amount of unused cache space is low GLYPH<SM590000> The amount of data in cache that must be premigrated is high GLYPH<SM590000> For RUN copies, an excessive amount of time is needed to complete an immediate copy The Cache Throttling graph displays the throttling that is applied to host write operations and  to inbound RUN copy operations. The delay represents the time delay, in milliseconds, per  32 KiB of transferred post-compressed data. Each numeric value represents the average of  values for all active partitions in the cluster. The following information is shown: GLYPH<SM590000> Cluster: The name of the affected cluster. GLYPH<SM590000> Copy: The average delay, in milliseconds, that is applied to inbound copy activities. GLYPH<SM590000> Write: The average delay, in milliseconds, that is applied to host write operations locally  and from remote clusters. 384  IBM TS7700 Release 5.0 Guide