Chapter 2 HPSS PlanningHPSS Installation Guide September 2002 135Release 4.5, Revision 22.10.3.3 System Memory and Paging Space RequirementsSpecific memory and disk space requirements for the nodes on which the HPSS servers will executewill be influenced by the configuration of the servers—both as to which nodes the servers will runon 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), excludingthe Movers, it is recommended that at least 1 GB of memory be configured. However, more memorywill certainly be required for systems that run most of the servers on one node and/or aresupporting many concurrent users. The availability of memory to the HPSS servers and SFS serverswill be critical to providing acceptable response time to many end user operations. Disk spacerequirements are primarily covered by Section 2.10.2, for SFS space, and the preceding subsectionsunder Section 2.10.3 for the individual HPSS servers. In addition, sufficient disk space should beavailable for paging space based on the recommendations made in the system documentation forthe amount of memory configured. Also, be aware that running many SAMMI clients on a machinewill quickly consume available system memory.For nodes that will only run Movers and no SFS server, the amount of memory is dependent on thenumber and types of devices configured on those nodes, the expected usage of those devices, andthe configuration of the Movers on those nodes. In general, Movers supporting a disk device willrequire more memory than Movers supporting tape devices. This is because many outstandingrequests are likely for a disk device, but there is usually only one outstanding request for a tapedevice. The size of the buffers used internally by the Mover will have an impact on the Movermemory requirements because each Mover request process will use two buffers to handle I/Orequests. 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 ConsiderationsThis section provides some additional hints for enhancing HPSS performance:Table 2-8 Paging Space InfoAmount ofphysicalmemoryMinimum recommended amount of pagingspace< 256MB 2 * amount of physical memory= 256MB and <1GB512MB + ((amount of physical memory – 256MB) * 1.25)= 1GB and < 2GB 1.5 * amount of physical memory= 2GB 1 * amount of physical memory
