Grid middleware usually makes use of several software modules that due to their complexity and development approach may have some latent bugs and leaks. These bugs can cause visible performance failures and undesired service crashes. To cope with this sort of transient failures we present a proactive software rejuvenation approach that exploits the use of virtualization middleware. To prove the effectiveness of our mechanism we decided to apply it to OGSA-DAI, a sound example of a middleware that has been widely used in several Grid-related projects. OGSA-DAI makes use of Tomcat/Axis as the SOAP