A file may be made more available in the face of failures of a file server if it appears on more than one file server. Availability is one of the main measures of the advantage of a replication algorithm. Performance - if a file is 'nearer' a user, access will generally be faster. Files may be replicated across local storage devices at creation time, or they may be 'cached' when first accessed. Portability - file access should be possible after a workstation is detached from the network if portability is required.
Replication carries with it several overheads.
Whole file copies are relatively expensive Consistency of Updates. There is cost in coordinating the update of a replicated file so that further accesses perceive a consistent object. This has an associated execution and communication cost. Some replication schemes may require complex software to implement. This has an associated implementation and maintenance overhead.