A consequence of Service Oriented Architectures is the burning need
to provide services at scale. The architecture that has evolved to
satisfy these requirements is a little known technique called the Cell
A Cell Architecture is based on the idea that massive scale requires parallelization and parallelization requires components be isolated from each other. These islands of isolation are called cells. A cell is a self-contained installation that can satisfy all the operations for a shard. A shard is a subset of a much larger dataset, typically a range of users, for example.
Cell Architectures have several advantages:
- Cells provide a unit of parallelization that can be adjusted to any size as the user base grows.
- Cell are added in an incremental fashion as more capacity is required.
- Cells isolate failures. One cell failure does not impact other cells.
- Cells provide isolation as the storage and application horsepower to process requests is independent of other cells.
- Cells enable nice capabilities like the ability to test upgrades, implement rolling upgrades, and test different versions of software.
- Cells can fail, be upgraded, and distributed across datacenters independent of other cells.