The second characteristic determines the type of the mount point. The majority of mount points are regular mount points. When the Cache Manager encounters a regular mount point, it checks the version of the fileset that the mount point indicates - read/write, read-only, or backup. If the read-only or backup version is indicated, the Cache Manager attempts to access that version. If the read/write version is indicated, the Cache Manager evaluates the type of fileset in which the mount point itself resides:
· If the regular mount point for a read/write fileset resides in a read/write fileset, the Cache Manager attempts to access only the read/write version of the fileset. If the read/write version does not exist or is inaccessible, the Cache Manager cannot access the fileset.
· If the regular mount point for a read/write fileset resides in a read-only fileset, the Cache Manager first attempts to access a read-only version of the fileset. If the fileset is not replicated, the Cache Manager attempts to access the read/write version of the fileset. If the fileset is replicated but all of the replicas are unavailable, the Cache Manager cannot access the fileset; it does not attempt to access the read/write version of the fileset.
Regular mount points allow the Cache Manager to retrieve files better than other types of mount points because regular mount points allow the Cache Manager to access read-only filesets whenever possible. There are normally several different instances of the read-only version of a fileset, but there is only one instance of the read/write version. Because more read-only copies are usually available, it is better to access the copies as often as possible.
A much less common type of mount point is a read/write mount point. Read-write mount points must name the read/write version of a fileset. When the Cache Manager encounters a read/write mount point, it attempts to access only the read/write version of the fileset, regardless of the type of fileset in which the mount point resides. If the read/write version does not exist or is inaccessible, the Cache Manager cannot access the fileset.
You usually mount read/write filesets with regular mount points. A regular mount point is explicitly not a read-only mount point. The Cache Manager can still access the read/write version of a fileset when it encounters a regular mount point if no read-only versions of the fileset exist or if the Cache Manager is already on a read/write traversal path.
The least common type of mount point is the global root mount point. This type of mount point is used to mount the root of the DCE global namespace. (Because it is maintained for backward compatibility with other file systems, it is not normally used. This documentation provides no examples of its use.)