A RAMADDA server can register its existence with one or more other RAMADDA servers. In this case, a RAMADDA server that is registering itself with a registry server is known as a "registry client".

The purpose of this is two-fold. First, this allows for a listing of RAMADDA servers so end users can find out about other repositories. Secondly, as part of the registration process your server will receive and store a list of all of the registered servers. You can then configure your RAMADDA server to support distributed searches across a federated network of RAMADDA servers (see below).

A RAMADDA server can also be enabled to be a registry for other servers. We term this a "registry server". This configuration is done through the Admin->Settings->Site and Contact Information page.

A registry server provides a listing of its known clients at:
https://ramadda.org/repository/registry/list

In the Admin->Settings->Site and Contact Information page there is a field where you can enter one or more registry servers, one per line. The format is:

some password:server url
e.g.:
thepasswordforramadda:https://ramadda.org/repository

You can also enable your server to be a registry server for other servers with the Enable this server to be a registry for other servers checkbox. You need to specify one or more passwords in a comma separated list. These are used in conjunction with the password specified in the above list of registry servers to authenticate the registration.

When your RAMADDA server receives a list of other RAMADDA servers as part of the registry process the server information is stored in the database. You can configure your server to provide remote search facilities on selected servers through the Admin->Remote Servers page.

In this form you can manually add new servers, delete and change existing servers and enable/disable servers. The basic registry service is used to support aggregated search across a set of RAMADDA servers. A client server will, on successful registration with a registry server, request the collection of client servers available from its registry server and store these in its database. The administrator of the client server will be able to select which of the other servers should be made available for federated search.

When there is such a collection of servers selected the Advanced Search form will have an entry listing the servers and will allow the end user to select which, if any, of the external servers should also be searched. When the search request is sent to the initial server if there are external servers selected that search will also be applied to those servers.