(3) Single master: Google embraced the concept of a single
master in their distributed system as a valuable tool to simplify
the design and make it more straightforward. Currently GFS uses
one master per cell [21], with multiple cells per data center. Even
though Google has worked around the issue this case underscores
the importance of scalability and the limitation of assigning different
levels of responsibility in any distributed system that is
expected to scale. The biggest weakness in this system that, the
Master can be the single point of failure. However, this can be overcome
by replicating the master state. The ‘‘Shadow Masters’’ can
provide read-only access in the absence of primary master.
(4) Overcompensated systems: CAP theorem explores tradeoffs
between Consistency, Availability, and Partition tolerance. CAP
theorem only discusses about the limitations in the face of certain
types of failures and does not constrain any system capabilities
during normal operation. CAP allows the system to guarantee
all of the ACID alongside high availability when there are no partitions
[22].