Hi, I've just read this blog post from Andy: http://www.epimorphics.com/web/wiki/epimorphics-builds-data-publish-platform-environment-agency
It describes a "quite simple" fault-tolerant and replicated data publishing solution using Apache Jena and Fuseki. Interesting. It's a master/slave architecture. The master (called by Andy in his post 'controller server') receives all updates and "calculates the triples to be added, the triples to be removed" so that changes are 'idempotent' (i.e. they can be reapplied multiple times (in the same order!) with the same effect). It would be interesting to know if the 'controller server' exposes a full SPARQL Update endpoint and/or the Graph Store HTTP Protocol and if that is the case how triples to be added/removed are calculated. (This is something I wanted to learn for a while, but I still did not find the time... a small example would be wonderful! ;-)). To conclude, I fully agree on the "quite simple design" and "simple systems are easier to operate". The approach described can work well in a lot of scenarios where the rate of updates/writes isn't excessive and you have mostly reads (which I still believe to be the case most of the times when you have RDF data, since data is often human generated/curated data). My hope is to see something similar in the 'open' so that other Apache Jena and Fuseki users can benefit from an highly available and open source publishing solution for RDF data (and they can focus their energies/efforts elsewhere: on the quality of their data modeling, data, applications, user experience, etc.). Paolo PS: Disclaimer: I don't work for Epimorphics, those are just my personal opinions and, last but not least, I love simplicity.
