Figure 6. The Relationship of Various Server Data Structures
Disk Storage Allocation
Each Core Server manages disk storage units for HPSS. It maps each disk storage unit onto an HPSS disk Physical Volume (PV) and records configuration data for the PV. Groups of one or more PVs (disk stripe groups) are managed by the server as disk Virtual Volumes (VVs). The server also maintains a storage map for each VV that describes which portions of the VV are in use and which are free. Figure 9: The Relationship of Various Server Data Structures shows the relationship of Core Server data structures such as VVs to other server data structures.
The server can manage information for any number of disk PVs and VVs; however, because a copy of all of the PV, VV, and storage map information is kept in memory while the server runs, the size of the server will be somewhat proportional to the number of disks it manages.
The Core Server is designed to scale up its ability to manage disks as the number of disks increase. As long as sufficient memory and CPU capacity exist, threads can be added to the server to increase its throughput. Additional subsystems can also be added to a system, increasing concurrency even further.
Tape Storage Allocation
Each Core Server manages serial access magnetic tape storage media for HPSS. The server maps each tape volume onto an HPSS tape PV and records configuration data for the PV. Groups of one or more PVs (tape stripe groups) are managed by the server as tape VVs. The server maintains a storage map for each VV that describes how much of each tape VV has been written and which storage segment, if any, is currently writable in the VV. Figure 9: The Relationship of Various Server Data Structures shows the relationship of data structures such as VVs to other server data structures.
The server can manage information for any number of tape PVs and VVs. It can also manage an unlimited number of tape PVs, VVs, maps, and segments without impacting its memory size.
HPSS Installation Guide | July 2008 |
Release 6.2 (Revision 2.0) | 82 |
