инет о webdav: http://ru.wikipedia.org/wiki/WebDAV

jakarta о load balancer: http://jakarta.apache.org/tomcat/tomcat-5.0-doc/balancer-howto.html
jakarta
Tomcat 5.0.15 and later ships with a webapp named balancer. This is a simple implemention of a rules-based load balancer. It was not designed as a replacement for other load-balancing mechanisms used for high traffic environments. Rather, it is a simple, pure Java, easily extensible, and fast way to direct traffic among multiple servers.

Although balancer ships with Tomcat, it is not Tomcat-specific and runs on other containers without any modification. The balancer webapp requires a Servlet Specification 2.3 or later container if you wish to use a filter to redirect traffic. If you wish to redirect traffic using a servlet, you may use any servlet container.