Koios¶
Koios is the previous-generation CEICO cluster. It has 27 compute nodes, each with two 16-core Intel Xeon Skylake CPUs (Xeon Gold 6130) and 384 GB of RAM. All nodes run Rocky Linux 9.8.
GPU node temporarily unavailable
The GPU node with four NVIDIA Tesla P100 cards is currently dedicated to a project and is not available through Slurm. It will return to general use later. Until then, use the A100 nodes on Phoebe for GPU work.
Accessing Koios¶
Log in through the front-end node koios1.fzu.cz (see SSH).
Koios shares accounts and SSH keys with Phoebe, so the same username and key work on both. Its
home directories are separate from Phoebe's.
Slurm partitions¶
Jobs on Koios are managed by Slurm. Jobs go to the cpu partition unless
you ask for another one with --partition.
| Partition | Nodes | Per node | Time limit | Use |
|---|---|---|---|---|
cpu (default) |
n[1-9,11-27] |
32 cores (64 threads), 384 GB | 9 days 1 h | batch jobs |
cpu_int |
n[11-12] |
32 cores (64 threads), 384 GB | 9 days 1 h | interactive work |
preempt |
n8 |
32 cores (64 threads), 384 GB | 9 days 1 h | jobs that may be preempted |
small_int |
s1 (virtual machine) |
8 cores, 23 GB | 7 days 7 h | jobs that need only a small node |
Limits change from time to time; sinfo on the login node shows the current values.
Hardware¶
| Node type | Amount | Hostnames | Processors | GPUs | Cores (logical CPUs) | Main memory | NVMe |
|---|---|---|---|---|---|---|---|
| compute | 27 | n[1-27] |
2× Xeon Gold 6130 | - | 32 (64) | 384 GB | 1× 2 TB |
| GPU | 1 | gpu2 |
2× Xeon Gold 6130 | 4× Tesla P100 SXM2 16 GB | 32 (virtual) | 293 GB | - |
The GPU node is a virtual machine. It uses 32 of the 64 logical CPUs of its physical server, and the four GPUs are passed through to it directly. It is currently dedicated to a project (see the note at the top of this page).
The nodes are connected by 100 Gb/s InfiniBand EDR (Mellanox MT4115 ConnectX-4 cards), a low-latency network for communication between nodes. More detail: Koios infrastructure.
Storage and software¶
Koios has its own home directories, software tree (/cvmfs/c9.phoebe.lan) and shared scratch
(/mnt/shared-scratch); the project space /mnt/proj is the same as on Phoebe. Each job gets a
private /tmp on the node's NVMe disk. See storage and software.