Setting up an LVM cache on an SSD can supercharge LVM.
A fast NoSQL DB, that uses the same RESP protocol and capable to store terabytes of data, also it integrates with your mobile/web apps to add real-time features, soon you can use it as a document store cause it should become a multi-model db. Uses Redis' network protocol so it's a drop-in replacement. Has some helper functions built in. Aims to be easy to use, with minimal configuration.
Redis is another key-value datastore (a distributed hash table, if you like) that can be used for either caching of often used objects or a database to build applications on top of. Can handle just about any serializable data structure, from strings to sets. Clusterable - uses master/slave replication. Written in C but has bindings for any programming language you're likely to know.
clustered cache key-value programming open-source nosql database
A website that lets you upload .torrent files and it'll cache them for up to six months (if nobody touches them) just in case the tracker goes down. Ideal for F/OSS projects because there aren't many trackers we can advertise on that aren't targets.
This is, incidentally, an open source project written in PHP with a project page on Github: https://github.com/torrage/Torrage
php github open-source filesharing storage bittorrent p2p cache torrents