There are several facilities that support a running Fedora repository. Each of them may be supplied by prepackaged default tools, or by externalized replacements. Which The choice of which to use for your installation depends on your local situation resources as well as what you expect to do with your repository.
Storage Configuration
TBD.
The Relational Database
TBD.
The Resource Index
The first question to ask about the Resource Index is whether or not you want to enable it at all. The Resource Index provides for fast SPARQL/iTQL/SPO queries against the graph of objects in your repository. Some advanced features of the Fedora platform depend on its availability, such as RDF-based queries to supply resource attributes for making policy-based access decisions. If you are not using these advanced features, and you do not expect to offer access to the RDF graph of your repository as a service, then you may wish to turn of the Resource Index, which you can do as an option in the Fedora installer.
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There isn't a single right choice for everyone in this decision. Some factors questions you may wish to consider include:
- Is supplying query access to the graph of objects in your repository very important to you? (If not, you may not need to enable to Resource Index.)
- Do you expect to use any of the advanced features of the Fedora service platform that require the presence of the Resource Index? (These include the use of Enhanced Content Models and RDF-based queries to supply resource attributes for making policy-based access decisions.)
- Do you expect to have a very large and sophisticated graph of objects? (If your graph is going to scale beyond a few million triples and you would like to be able to query it, you may want to consider an external triplestore.)
- How much time and effort can you commit to supporting your repository? (An external triplestore offers more functionality than the built-in, but also requires more work than the built-in.)
- Are you very interested in exploring Fedora semantic graph capabilities? (An external triplestore is the most flexible and customizable configuration for the Resource Index.)
It is to be noted that creation of a Resource Index and migration from a built-in triplestore to an external triplestore are supported by Fedora's command-line utilities, so the decision you make at installation need not be final. If you do not have a clear reason in your mind why you would want to use the Resource Index, you can safely leave it off, and if you do know that you will want to use the Resource Index but do not have a clear reason to use an external triplestore, you can safely use the built-in triplestore.