Virtual Ad Hoc Network (VAN) testbed aims at achieving large scale application testing for ad hoc networks by integrating host virtualization and network simulation. Efficient use of storage space is essential for such testbeds. Storage redundancy resulting from duplicated files and application installations across the virtual machines in a large scale testbed (> a few hundred VMs) can be significantly reduced by using storage sharing techniques. Although Content Addressable Storage (CAS) along with Copy-on-write can remove storage redundancy at block-level, it requires hash computation for every write operation that incurs considerable online computation overhead.