UCLA

Virtual Desktop Infrastructure (VDI) deployments run large numbers of desktops in a virtualized environment to increase flexibility and address cost. One of the major challenges VDI faces today is the cost of high bandwidth interconnection networks to shared storage. VDI storage workloads have a number of unique characteristics which make them a target for optimization. For example, VDI workloads exhibit high amount of redundant data transfers (from shared OS images), highly bursty behavior (from daily work patterns), and a common storage format (virtual disks).

This thesis performs a detailed study of VDI workload and evaluates effectiveness of four hypervisor side optimization techniques. To eliminate network read requests and serve data from locally cached blocks, we evaluate two read caches, namely, location-addressed and content-addressed. We also compare these read cache with a simple mechanism which stores shared read-only virtual disks on hypervisor side local media. To eliminate transfer of redundant data that is written to the storage server, we evaluate the effectiveness of inline write deduplication. All the experiments are carried out in two setting, for full clone virtual desktops and linked clone virtual desktops.

A detailed trace-driven simulation study of the mechanisms with a realistic VDI workload shows up to 75% reduction in the total network I/O traffic. We propose some recommended setting for choosing the right optimizations, for example, for full clone virtual desktops content-addressed cache outperforms location-addressed cache by 50%.