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Table 11-4 lists the indirection layer algorithm in a multi-target FlashCopy. 

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## Stopping process in a multiple target FlashCopy: Cleaning Mode 

When a mapping that contains a target that includes dependent mappings is stopped, the mapping enters the stopping  state. It then begins copying all grains that are uniquely held on the target volume of the mapping that is being stopped to the next oldest mapping that is in the copying state. The mapping remains in the stopping  state until all grains are copied, and then enters the stopped  state. This mode is referred to as the Cleaning Mode . 

For example, if the mapping Source-T2 was stopped, the mapping enters the stopping  state while the cleaning process copies the data of T2 to T1 (next oldest). After all of the data is copied, Source-T2 mapping enters the stopped  state, and T1 is no longer dependent upon T2. However, T0 remains dependent upon T1. 

For example, as shown in Table 11-3 on page 479, if you stop the Source-T2 mapping on “Time 7,” then the grains that are not yet copied on T1 are copied from T2 to T1. Reading T1 is then like reading the source at the time T1 was started (“Time 2”). 

As another example, with Table 11-3 on page 479, if you stop the Source-T1 mapping on “Time 8,” the grains that are not yet copied on T0 are copied from T1 to T0. Reading T0 is then similar to reading the source at the time T0 was started (“Time 0”). 

If you stop the Source-T1 mapping while Source-T0 mapping and Source-T2 are still in copying mode, the grains that are not yet copied on T0 are copied from T1 to T0 (next oldest). T0 now depends upon T2. 

Your target volume is still accessible while the cleaning process is running. When the system is operating in this mode, it is possible that host I/O operations can prevent the cleaning process from reaching 100% if the I/O operations continue to copy new data to the target volumes. 

