With the emergence of Storage Networking, distributed file systems that allow data sharing through shared disks will become vital. We refer to Cluster File Systems as a distributed file systems optimized for environments of clustered servers. The requirements such file systems is that they guarantee file systems consistency while allowing shared access from multiple nodes in a shared-disk environment. In this paper we evaluate three approaches for designing a cluster file system - conventional client/server distributed file systems, symmetric shared file systems and asymmetric shared file systems. These alternatives are considered by using our prototype cluster file system, HAMFS (Highly Available Multi-server File System). HAMFS is classified as an asymmetric shared file system. Its technologies are incorporated into our commercial cluster file system product named SafeFILE. SafeFILE offers a disk pooling facility that supports off-the-shelf disks, and balances file load across these disks automatically and dynamically. From our measurements, we identify the required disk capabilities, such as multi-node tag queuing. We also identify the advantages of an asymmetric shared file system over other alternatives.