This illustrates an instance requesting a changed block for a modification operation.
The three main components in this illustration are the Global Cache Service, Instance 1, and Instance 2.
In step 1, instance 1 submits a request to the Global Cache Service to modify the block. The GCS then forwards the request to the holding instance, which in this case, is instance 2. Instance 2 then transmits the block to instance 3 after the processing is completed as described in Step 3 in the surrounding text. After instance 1 receives the block, instance 1 informs the GCS that it holds the block in exclusive mode as described in Step 4.