Sigma is a 110-node HPC cluster funded by and dedicated to Linköping University users. 108 of these nodes are regular CPU compute nodes, and two of the nodes are equipped with 4x Tesla V100 GPUs.
Sigma replaced the previous cluster Gamma in August 2018.
Sigma is very similar to NSC's much larger Tetralith cluster. This allows LiU users to easily move to Tetralith when the Sigma resources are insufficient.
Sigma is running a CentOS 7 version of the NSC Cluster System Environment. This means that most things are very familiar to Gamma users.
Sigma CPU compute nodes have 32 CPU cores. There are 104 "thin" nodes with 96 GiB of primary memory (RAM) and 4 "fat" nodes with 384 GiB. Each compute node has a local SSD disk where applications can store temporary files (approximately 200GiB per thin node, 900GiB per fat node).
The Sigma GPU compute nodes each have; 2x Intel Xeon Gold 6240 CPU (36 CPU cores in total), 4x NVIDIA Tesla V100 32GB GPUs, 384 GiB primary memory and 2x 7680GB NVMe SSDs for fast node local flash storage.
All Sigma nodes are interconnected with a 100 Gbps Intel Omni-Path network which is also used to connect the existing storage. The Omni-Path network is similar to the FDR Infiniband network in Gamma (e.g still a fat-tree topology).
The hardware was delivered by ClusterVision B.V.
Sigma applications (note: all Tetralith applications are available on Sigma)