Description of the SGI Altix 3700 Aster system
Aster is an SGI Altix 3700 system, consisting of 416 CPUs (Intel Itanium 2,
1,3 GHz, 3 Mbyte cache each), 832 Gbyte of memory and 2.8 Tbyte of scratch disk
space. The total peak performance is 2.2 Teraflop/sec.
The 416 processors are divided over 5 nodes: 4 batch nodes and
1 interactive node:
| type | processors | Gbytes memory | Gbytes scratch | nodes |
| interactive | 32 | 64 | 400 | 1 |
| batch | 64 | 128 | 400 | 2 |
| batch | 128 | 256 |
800 |
2 |
Architecture
Every node in Aster is a CC-NUMA machine. The term CC-NUMA stands for
Cache-Coherent Non Uniform Memory Access. In the CC-NUMA model, the system
runs one operating system and shows only a single memory image to the user
eventhough the memory is physically distributed over the processors. Since
processors can access their 'own' memory (i.e. memory on the same
physical board as the processor) much faster than that of other
processors, memory access is non uniform (NUMA). In this architecture the
contents of the various processor caches should be coherent requiring extra
hardware and a cache coherency protocol. A NUMA computer fulfilling these
requirements is called a CC-NUMA machine. See also
CC-NUMA architecture.
