DEC user documentation¶
Disclaimer: This website is a work in progress. If you have any questions or suggestions, please open an issue.
Introduction¶
The DEC is an HPC cluster of 30 hyper-threaded machines connected on 2 networks: an ethernet at 1 Gb/s (soon at 10 Gb/s) and an Infini Band at 40 Gb/s. This center has 812 cores (the double of threads), 15 TBytes of memories and 300 Tbytes of disks. The generic name of the different machines is "mardec" (for Marseille Dark Energy Center): - mardec: Master machine with 20 cores (40 threads) and 250 Gbytes of memories. It is not recommended to use it for any calculation. - mardec00: This machine is designed for high memory calculations, with 28 cores (56 threads) and 1.5 TBytes of memories. This machine is slightly slower (10%) than the rest of the cluster. It is therefore preferable not to use it in parallel with other nodes in the cluster at the risk to slow down by 5-10% the total execution time. However, nothing prohibits you from using it. - mardec01 to mardec28: These 28 machines are each equipped with 28 cores (56 threads) and 0.5 TBytes of memory and 300 Gbytes of internal disk (/ data). This is the heart of DEC.
Access¶
To access the DEC, you need to be a member of the CPPM group or a direct collaborator of a member of the CPPM group. If you are a member of the CPPM group, you should already have access to the DEC. If you are not, please contact the DEC administrator via the issue tracker to request access.
The DEC is accessible via ssh at the address mardec.in2p3.fr. The DEC nodes are accessible via the mardec00 to mardec28 addresses from the CPPM network. To access the DEC from outside the CPPM network, you must configure a ssh rebound on the mardec.in2p3.fr address.
Connection to the DEC is done via ssh with the following command:
ssh <username>@mardec.in2p3.fr
We recommend that you use a ssh key to connect to the DEC. To do this, you must first generate a key pair on your local machine with the following command:
ssh-keygen -t ed25519
Then you must copy the public key to the DEC with the following command:
ssh-copy-id <username>@mardec.in2p3.fr
To configure a ssh rebound, you must add the following lines to your ~/.ssh/config file:
Host mardec.in2p3.fr
User <username>
IdentityFile <path to your private key>
Host mardec??.in2p3.fr
ProxyJump mardec.in2p3.fr
User <username>
IdentityFile <path to your private key>
With this configuration, you can connect to the DEC nodes from anywhere with the following command:
ssh mardec24.in2p3.fr # for example
And you can still connect to the DEC node directly from the CPPM network:
ssh mardec24 # for example