Gateway Types
Syndicate offers three types of gateways
User Gateway (UG)
User gateways interface with the application, and run as co-located processes alongside it. The gateway presents a well-defined storage API to co-located applications, such as a POSIX filesystem or an HTTP RESTful service. When the application reads data, the user gateway contacts other gateways to pull in the requested chunks of data. When the application writes data, it forwards the written chunks to other gateways for storage.
Replica Gateway (RG)
Replica gateways interface with back-end read/write storage systems, like Amazon S3. They take chunks of data from user gateways and make them persistent, and later serve the chunks back.
Acquisition Gateway (AG)
Acquisition gateways crawl external datasets and make them available to user gateways in a read-only fashion.