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Additional Layers and Resources

In addition to the four main layers, we have the storage resources & transfer tools, as well as the underlying persistent layers. These are represented in the architecture diagram by the different queuing systems, transactional relational databases, & analytics storage on non-relational databases.

  • Storage & Transfer Tools layer

The Storage layer is responsible for the various interactions with different grid middleware tools & storage systems. The transfer tool interface is a feature of Rucio that enables the daemons to submit, query, and cancel transfers generically & independently from the actual transfer service being used.

This layer is not a software that resides in a datacenter but is more representative of the various abstractions in a storage system. It can be configured dynamically & centrally to suite requirements.

  • Persistence Layer

This is the layer responsible for keeping all the data & application states for all daemons. Also known as the catalog, it requires a transactional database.

The persistence layer supports many different types of transactions relational database management systems such as SQLite, MySQL, PostgreSQL, or Oracle. Both upgrading & downgrading of the database schema are supported.