"Skylable was founded in 2012 by Tomasz Kojm, Luca Gibelli, Edwin Török and Alberto Wu, best known for their success with ClamAV, the leading GPL anti-virus for UNIX running on millions of servers and protecting billions of users."
http://www.skylable.com/products/sx/
"With SX Cluster you aggregate the disk space available on multiple servers and merge it into a single storage system. The cluster makes sure that your data is always replicated over multiple nodes (the exact number of copies is defined by the sysadmin) and synchronized. Additionally Sx has built-in support for deduplication, client-side encryption, on-the-fly compression and much more"
Very responsive in their IRC channel on Freenode too. I know I sound like a walking advert reading this comment back but I have no affiliation other than end user
Are there use cases where Swift is a better fit than Cassandra?
Here are good overviews:
* http://docs.openstack.org/developer/swift/
* https://swiftstack.com/blog/2012/09/16/globally-distributed-...
And how Rackspace runs it at scale;
* https://www.openstack.org/summit/openstack-summit-hong-kong-...
http://docs.openstack.org/developer/swift/
It can be run as a stand alone app so it's generally pretty simple and can include support from https://swiftstack.com/.