Persons and businesses may desire to isolate various computing systems without using additional hardware. In these situations virtual machines may be useful. A cluster virtualization system may contain multiple hosts, or virtualization servers, that execute one or more virtual machines. The virtualization system may use a virtual machine file system that references metadata. The metadata may map data to a target virtual machine. Multiple hosts in the cluster virtualization system may share a metadata storage system, but may fail to share application data or data other than metadata.
Writing data to a data storage shared by multiple virtualization servers may take a relatively long time. Accordingly, it may be desirable to cache at least some of the data at the virtualization server instead of at the shared data storage. Unfortunately, caching metadata at a virtualization server may create inconsistencies, because the multiple virtualization servers may share metadata even if they do not share application data or data other than metadata.