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Chapter 2 HPSS Planning
HPSS Installation Guide September 2002 135
Release 4.5, Revision 2
2.10.3.3 System Memory and Paging Space Requirements
Specific memoryand disk space requirements for the nodes on which theHPSS servers will execute
will be influenced by the configuration of the servers—both as to which nodes the servers will run
on and the amount of concurrent access they are set up to handle.
For nodes that will run one or more of the HPSS servers (and most likely an SFS server), excluding
the Movers, it is recommended that at least 1 GB of memory be configured. However, more memory
will certainly be required for systems that run most of the servers on one node and/or are
supporting many concurrent users. The availability of memory to the HPSS servers and SFS servers
will be critical to providing acceptable response time to many end user operations. Disk space
requirements are primarily covered by Section 2.10.2, for SFS space, and the preceding subsections
under Section 2.10.3 for the individual HPSS servers. In addition, sufficient disk space should be
available for paging space based on the recommendations made in the system documentation for
the amount of memory configured. Also, be aware that running many SAMMI clients on a machine
will quickly consume available system memory.
For nodes that will only run Movers and no SFS server, the amount of memory is dependent on the
number and types of devices configured on those nodes, the expected usage of those devices, and
the configuration of the Movers on those nodes. In general, Movers supporting a disk device will
require more memory than Movers supporting tape devices. This is because many outstanding
requests are likely for a disk device, but there is usually only one outstanding request for a tape
device. The size of the buffers used internally by the Mover will have an impact on the Mover
memory requirements because each Mover request process will use two buffers to handle I/O
requests. It is recommended that at least 512 MB of memory be configured for these nodes.
However, more memory will certainly be required for nodes that are supporting many devices,
especially disk devices that will support a large number of concurrent end-user requests.
Paging space should be sized according to the following rules:
2.11 HPSS Performance Considerations
This section provides some additional hints for enhancing HPSS performance:
Table 2-8 Paging Space Info
Amount of
physical
memory
Minimum recommended amount of paging
space
< 256MB 2 * amount of physical memory
= 256MB and <
1GB
512MB + ((amount of physical memory – 256MB) * 1.25)
= 1GB and < 2GB 1.5 * amount of physical memory
= 2GB 1 * amount of physical memory