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Welcome to SRVOAD user guide... We are looking for a Phd student to manage SRVOAD (creating account, helping new users, etc).

What is SRVOAD ?

SRVOAD is a shared computation server used by members of TASK and MODELIS teams. To use it please contact one of the administrators:

• Charles PRUD'HOMME (charles.prudhomme@imt-atlantique.fr)
• Nicolas PIERRE (nicolas.pierre2@imt-atlantique.fr)

Good practice

1. Using job arrays is the best practice to run your code with slurm and optimize memory and cpu allocation.
2. Slurm users are free to use hard limits (e.g. job is killed when it exceed the memory allocation) or soft limits. Using hard limit is the best way to be sure that your benchmark will not alter other users benchmarks.

Common errors

1. With htop you will see 80 threads available. The server is composed of 40 physical cpus (core) with hyperthreading (not 80). A single physical CPU will never be used to run two different tasks. The cpus-per-task option defines the number of threads you want to use. If you ask for an odd number of threads, slurm will always allocate the even number above (ie. cpus-per-task=1 slurm will allocate 2 threads per task).
2. If you use an SBATCH script to run your code, don't use srun in it. In fact, using srun commands in a SBATCH script is equivalent to using "srun srun my_app" and often lead to problems (e.g. different settings).
3. Every interactive process has a limit of 2GB of RAM, even with salloc or srun. sbatch is not affected by this limit.

Know your machine

A DELL R440 1U server

Connection

• Connection by SSH with your login (can be different from your school login) and initial password

ssh <login>@srvoad.imta.fr

• If you are not physically on the school network you need to use the proxy fbi.emn.fr. The proxy is removed since 04/03/2024 by the DISI. You need to configure your VPN using this procedure. With the vpn activated you can connect as if you were at the school.

• Change your initial password, if by any mean you lost your password you can ask an administrator for help.

passwd

• Transferring a file with scp (-r for a repository)

scp <my file> <login>@srvoad.imta.fr:<path-to-my-file>

User environment

• What is slurm ?
• Basic guide to Slurm
• Softwares installed
• How to execute my code
• Job Array and configuration file