iRODS Demos: Data Grid Topology

One of my responsibilities at RENCI is to set up and present iRODS demos for customers. Over the coming weeks, I will describe my experiences setting up these demonstrations.

The first thing to understand is how data grids are structured in iRODS. I made this simple little diagram to help:

iRODS Zone Topology

An iRODS Zone– Each iRODS deployment is an individual Zone with a single set of management policies and a single metadata catalog. Usually, an iRODS Zone will be spread over multiple machines (iCAT servers and resource servers).

iCAT Server – The essential element of any iRODS Zone is an iCAT Server. The iCAT is a database (presently Postgres, MySQL, or Oracle) that holds metadata about the data stored in iRODS.

Resource Servers – Resource servers host data collections. Each resource server in a Zone connects to a single iCAT server. The iCAT server provides the resource server with the information necessary for policy enforcement.

Federation – Federation is the connection between two iRODS Zones. Users from one Zone can access data from another, with restrictions determined by the administrator of the host Zone. Federation is brokered between ICAT servers.

In my next post, I’ll describe how to set up an iCAT-enabled resource server, which combines the functionality of an iCAT server and a resource server on the same machine.