dCache is a disk cache. More description will be written later, see the links below for more about dCache.
The VDT has packaged dCache to be easy to install and configure. We're still working on it, but you can try it out. Please note that it is currently not provided as part of Pacman, but as a few RPMs and a script that installs the RPMs and edits the configuration files. Download it from the link below, and read the README file.