Use LVM thin LV on cache LV
As of the LVM release 2.02.106, LVM supports the use of fast block devices (such as SSD drives) as write-back or write-though caches for larger slower block devices.
The cache logical volume type uses a small and fast LV to improve the performance of a large and slow LV. It's based on dm-cache(the kernel driver), so you can only use it on CentOS7.1/Ubuntu 15.04 or later.
For this article, I will assume you using Ubuntu 15.04.