9df2339f9b
Master images of non-trivial filesystems will run 3+G (even though the qcow2 might be < 1G) so we need to make it big enough to be useful :). Ideally we'd autotune this based on free space or something, but for now, this is large enough to cache e.g. TripleO cluster workloads but small enough to fit in test VMs. This patch sets the default cache to 20G. Change-Id: I11ca629589e8a90f727abcc5b1c7e72dbd9e4b0f