Ceph scalability and high availability
To understand Ceph scalability and high availability, let's first talk about the architecture of traditional storage systems. Under this architecture, to store or retrieve data, clients talk to a centralized component known as a controller or gateway. These storage controllers act as a single point of contact for a client's request. The following diagram illustrates this situation:
This storage gateway, which acts as a single point of entry to storage systems, also becomes the single point of failure. This also imposes a limit on scalability and performance while a single point of failure is being introduced, such that the whole system goes down if the centralized component goes down.
Ceph does not follow this traditional storage architecture; it has been totally reinvented for the next-generation of storage. Ceph eliminates the centralized gateway by enabling the clients to interact with the Ceph OSD daemons directly. The following diagram illustrates...
