After removal begins, the TS7700 continues to remove virtual volumes until the stop threshold is met. The stop threshold is a value that is the removal threshold minus 500 GB. A particular virtual volume cannot be removed from a TS7700 cache until the TS7700 verifies that a consistent copy exists on a peer cluster. 

If a peer cluster is not available or a volume copy is not yet completed, the virtual volume is not a candidate for removal until the appropriate number of copies can be verified later. Time delayed replication can alter the removal behavior. 

Tip:  This field is visible only if the selected cluster is a TS7700 in a grid configuration. 

## Temporary removal threshold 

The temporary removal threshold lowers the default removal threshold to a value lower than the stop threshold in anticipation of a service mode event, or before a DR test where FlashCopy for DR testing is used. 

Virtual volumes might need to be removed before one or more clusters enter service mode. When a cluster in the grid enters service mode, remaining clusters can lose their ability to make or validate volume copies, which prevents the removal of enough logical volumes. This scenario can quickly lead to the TS7700 cache reaching its maximum capacity. 

The lower threshold creates more free cache space, which enables the TS7700 to accept any host requests or copies during the service outage without reaching its maximum cache capacity. 

The temporary removal threshold value must be greater than or equal to (>=) the expected amount of compressed host workload that is written, copied, or both to the TS7700 during the service outage. The default temporary removal threshold is 4 TB, which provides 5 TB (4 TB plus 1 TB) of existing free space. You can lower the threshold to any value from 2 TB to full capacity minus 2 TB. 

All TS7700 clusters in the grid that remain available automatically lower their removal thresholds to the temporary removal threshold value that is defined for each one. Each TS7700 cluster can use a different temporary removal threshold. The default temporary removal threshold value is 4 TB or 1 TB more data than the default removal threshold of 3 TB. Each TS7700 cluster uses its defined value until the originating cluster in the grid enters service mode or the temporary removal process is canceled. The cluster that is starting the temporary removal process does not lower its own removal threshold during this process. 

## 4.2.7 Data management settings (TS7700T CPx in a multi-cluster grid) 

The following settings for the TS7700 are optional, and they can be configured during the installation of the TS7700, or later by using the TS7700 LIBRARY REQUEST (LI REQ)  command interface: 

GLYPH<SM590000> Copies to Follow Storage Class Preference (COPYFSC) 

GLYPH<SM590000> Recalls Preferred to be Removed from Cache (RECLPG0) 

Note:  For more information about the Host Console Request functions and their responses, see IBM Virtualization Engine TS7700 Series z/OS Host Command Line Request User’s Guide , WP101091. 

