345Consistency Management in Cloud Storage Systems
that processes client requests for data hosted on the storage engine (a relational
database). Generator operations are performed on a temporary private scratchpad,
resulting in a virtual private copy of the service state. Upon the completion of a gen-
erator operation, the proxy server sends the shadow operation to the concurrency
coordinator. The latter noties the proxy server whether the operation is accepted
or rejected according to the RedBlue consistency. If accepted, the operation is then
delegated to the local data writer to be executed in the storage engine.
10.5.2 ConsistenCy rationing
Data created and processed by the same application might be different, and so might
the consistency ...