No, it is a feature that is comparable to bcache, Flashcache, EnhanceIO or dm-cache, it is a user friendly version of dm-cache. Look here: http://man7.org/linux/man-pages/man7/lvmcache.7.html http://blog.kylemanna.com/linux/2014/07/28/disk-caching-kernel-tree-benchmarks-using-dm-cache--lvmcache/ http://blog-vpodzime.rhcloud.com/?p=45 My first functionality tests showed, that using lvmcache for the /boot and /root is problematic. System refuses to boot because of a missing binary in the initramfs that is necessary to start a cached volume and grub2 also cannot use a cached volume.