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Chapter 1 HPSS Basics
HPSS Installation Guide September 2002 29
Release 4.5, Revision 2
exactly one PVR. Multiple PVRs are supported within an HPSS system. Each PVR is
typically configured to manage the cartridges for one robot utilized by HPSS.
For information on the types of tape libraries supported by HPSS PVRs, see Section 2.4.2:
Tape Robots on page 54.
An Operator PVR is provided for cartridges not under control of a robotic library. These
cartridges are mounted on a set of drives by operators.
• Mover (MVR). The purpose of the Mover is to transfer data from a source device to a sink
device. A device can be a standard I/O device with geometry (e.g., tape, disk) or a device
without geometry (e.g., network, memory). The MVR’s client (typically the SS) describes
the data to be moved and where the data is to be sent. It is the MVR’s responsibility to
actually transfer the data, retrying failed requests and attempting to optimize transfers.
The MVR supports transfers for disk devices, tape devices and a mover protocol that can
be used as a lightweight coordination and flow control mechanism for large transfers.
• Storage System Management (SSM). SSM roles cover a wide range, including aspects of
configuration, initialization, and termination tasks. The SSM monitors and controls the
resources (e.g., servers) of the HPSS storage system in ways that conform to management
policies of a given customer site. Monitoring capabilities include the ability to query the
values of important management attributes of storage system resources and the ability to
receive notifications of alarms and other significant system events. Controlling capabilities
include the ability to start up and shut down servers and the ability to set the values of
management attributes of storage system resources and storage system policy parameters.
Additionally, SSM can request that specific operations be performed on resources within
the storage system, such as adding and deleting logical or physical resources. Operations
performed by SSM are usually accomplished through standard HPSS Application Program
Interfaces (APIs).
SSM has three components: (1) the System Manager, which communicates with all other
HPSS components requiring monitoring or control, (2) the Data Server, which provides the
bridge between the System Manager and the Graphical User Interface (GUI), and (3) the
GUI itself, which includes the Sammi Runtime Environment and the set of SSM windows.
• Non-DCE Client Gateway (NDCG). NDCG provides an interface into HPSS for client
programs running on systems lacking access to DCE or Encina services. By linking the
Non-DCE Client API library, instead of the usual Client API library, all API calls are routed
through the NDCG. The API calls are then executed by the NDCG, and the results are
returned to the client application. Note that the NDCG itself must still run on a system with
DCE and Encina, while it is the client application using the Non-DCE Client API that does
not suffer this restriction.
1.3.3 HPSS Storage Subsystems
Storage subsystems have been introduced starting with the 4.2 release of HPSS. The goal of this
design is to increase the scalability of HPSS by allowing multiplename and bitfile servers tobe used
within a single HPSS system. Every HPSS system must now be partitioned into one or more storage
subsystems. Each storage subsystem contains a single name server and bitfile server. If migration
and purge are needed, then the storage subsystem should contain a single, optional migration/
purge server. A storage subsystem must also contain one or more storage servers, but only one disk
storage server and one tape storage server are allowed per subsystem. Name, bitfile, migration/