A cluster of computer system nodes share direct read/write access to storage devices via a storage area network using a cluster filesystem and operating system implementing DMAPI. Threads executing on a metadata client know when a DMAPI event is required, and generate the DMAPI event on their own initiative when necessary. A metadata server maintains DMAPI queues. If the metadata server relocates to another host, the DMAPI events in the DMAPI queues are moved transparently to users.