| dc.description.abstract | Virtual machine technologies offer simple and practical mechanisms to address
many manageability problems in database systems. For example, these
technologies allow for server consolidation, easier deployment, and more flexible
provisioning. Therefore, database systems are increasingly being run on
virtual machines. This offers many unique opportunities for database research. However, it is also important to understand the
cost of virtualization. Virtual machine technologies add a layer of indirection between applications and the hardware that they use (e.g. CPU, memory, disk). This added complexity results in a performance overhead for software systems running in a virtual machine. In this thesis, we present an experimental study of the overhead of running a database workload in a virtual machine. Using a TPC-H workload running on PostgreSQL in a Xen
virtual machine environment, we show that Xen does indeed introduce overhead
for system calls, page fault handling, and disk I/O. However, these overheads
do not translate to a high overhead in query execution time. We show that in all cases the
average overhead is less than 10% and, therefore, conclude that the advantages of running a database system in a virtual
machine do not come at a high cost in performance. | en |
