Location-independent naming means that a distinction now exists between a file’s
logical name and its physical name on NonStop systems. Previously, the file name has
always indicated its physical location; that is, the name of each file indicated the node
and physical volume on which the file was located. For example, the file name
\SYSA.$DATA.ACTIVE.PAYABLES identifies a file (PAYABLES) that resides on a node
named \SYSA, on a volume named $DATA, on a subvolume named ACTIVE.

With SMF, the file \SYSA.$DATA.ACTIVE.PAYABLES can reside on any physical
volume. With the exception of the node name, the name of a file managed by SMF is
independent of its location.

SMF controls the mapping of the logical name to the physical name. This strategy
allows the physical name, which identifies the file’s physical location, to change when a
file is moved to a different location, while the logical name remains the same to
applications and to users.

Impact on Existing Systems and Applications

Location-independent naming is designed to have minimal effect on the operation of
NonStop systems and user applications. For example:



Applications need not change when the files they access are physically relocated
to other volumes in the same storage pool.



Most existing applications continue to function correctly without change after file
names are converted and become location-independent.



SMF has only a slight performance impact on operations involving logical names,
but has no impact on read/write operations after a file is opened.



SMF does not increase the downtime of applications and, in fact, improves service
availability when volumes are down.

Storage Pools

A storage pool is a collection of physical disk volumes managed by SMF. All of the
physical disks in a storage pool must be on the same system. Up to 6,144 physical
disk volumes may be placed in a pool. A physical disk volume can be in only one
storage pool at any given time.