Linux SSD caching (dm-cache)

The Linux 3.9 kernel (made available on April 28, 2013) introduces SSD caching. The kernel’s Device mapper now includes a cache target called dm-cache that enables SSDs or other storage device to be used as a cache for a hard drive. It essentially speeds up data writes and reads as it allows the faster SSD to first cache data and then transfer it to the slower hard drive.