First up, Canonical's server team for Ubuntu has decided on BCache as the preferred means of SSD caching on the Ubuntu Server. BCache allows for an SSD to be used as a read/write cache for another block device, which is generally a traditional HDD. BCache is an alternative to Flashcache, EnhanceIO, and other Linux SSD caching alternatives. Ubuntu developers will add BCache packages to the Ubuntu universe archive for the Utopic Unicorn release. BCache is also being pursued for packaging within upstream Debian.
Those wishing to learn more about BCache should visit the always-great documentation on the Arch Linux Wiki.
More details on the Ubuntu Server 14.10 plans can be found via summit.ubuntu.com and the Launchpad Blueprint.