The Atos HPCF consists of four virtually identical complexes: AA, AB, AC and AD. In total, this HPCF features 8128 nodes:
- 7680 compute nodes, for parallel jobs
- 448 GPIL (General Purpose and Interactive Login) nodes, which are devised to integrate the interactive and post-processing work from older platforms such as the Cray HPCF, ECGATE and Linux Clusters.
Access for Cooperating States users and those from Member States with no formal HPCF privileges
There is an additional virtual complex, ECS, which is made from compute nodes of the 4 complexes. This is the one to be used by those users who don't have access to the full HPCF service.
The logic structure of one of the complexes is as follows:
Main differences with the previous Cray XC40 system
The most notable change with respect to the previous Cray XC40 HPCF is in the processor architecture, from Intel to AMD. Although both implement the x86_64 instruction set, the latter has many more cores.
| Cray (CCA/CCB) | Atos (AA/AB/AC/AD) | |
|---|---|---|
| CPU Architecture | Intel Broadwell | AMD EPYC Rome |
Core Frequency | 2.1 GHz | 2.5 GHz (GPIL) / 2.25 GHz (compute) |
| Cores per node (HT) | 36 (72) | 128 (256) |
| Memory per node | 128 GiB | 512 GiB (GPIL) / 256 GiB (compute) |
| Fabric interconnect | Cray Aries | Mellanox HDR InfiniBand - 100 Gbps (GPIL) / 200 Gbps (compute) |
| Operating System | Based on SLES 11 | Based on RHEL 8 |
| Batch system | PBS with ALPS | SLURM |
| Parallel Filesystem | Lustre | Lustre |
| Compilers | Cray, GNU, Intel | GNU, Intel, AOCC |
| MPI | Cray MPICH | Intel MPI, OpenMPI |