Is there a business proven cloud store / Key=>Value Database?

Question

I have been looking for cloud computing / storage solutions for a long time (inspired by the Google Bigtable). But I can't find a easy-to-use, business-ready solution.

I'm searching a simple, fault tolerant, distributed Key=>Value DB like SimpleDB from Amazon.

I've seen things like:

The CouchDB Project : Simple and distributed, fault-tolerant Database. But it understands only JSON. No XML connectors etc.

Eucalyptus : Nice Amazon EC2 interfaces. Open Standards & XML. But less distributed and less fault-tolerant? There are also a lot of open tickets with XEN/VMWare issues.

Cloudstore / Kosmosfs : Nice distributed, fault tolerant fs. But it's hard to configure. Are there any java connectors?

Apache Hadoop : Nice system which much more then abilities to store data. Uses its own Hadoop Distributed File System and has been testet on clusters with 2000 nodes.

*Amazon SimpleDB : Can't find an open-source alternative! It's a nice but expensive system for huge amounts of data. And you're addicted to Amazon.

Are there other, better solutions out there? Which one is the best to choose? Which one offers the smallest amount of SOF(Singe Point of Failure)?

Answer 1

MongoDB is also an option here. It's quite similar to CouchDB but instead of using map/reduce in Javascript, it uses a query language similar to SQL. MongoDB supports indexes, replication, query profiling and more.