I'm trying to set up a test server to test and benchmark flashcache based on the instructions found here: http://florianjensen.com/2013/01/02/adding-flashcache-to-proxmox-and-lvm/ I have installed Proxmox 3.1, and updated all packages to latest. Unfortunately, I can't install the pve-headers package. Anyone got the faintest idea why this is happening? Code: root@proxmox:~# uname -a Linux proxmox 2.6.32-23-pve #1 SMP Tue Aug 6 07:04:06 CEST 2013 x86_64 GNU/Linux root@proxmox:~# apt-get install pve-headers-2.6.32-23-pve Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package pve-headers-2.6.32-23-pve E: Couldn't find any package by regex 'pve-headers-2.6.32-23-pve'