= System usage =

The system can be used through the SLURM based batch system that is also used for the DEEP-EST Cluster Module and (most of) the remaining compute nodes.You can request cluster nodes on the SDV with an interactive session like this:

{{{
srun --partition=sdv -N 4 -n 8 --pty /bin/bash -i
srun ./hello_cluster 

Hello world from process 6 of 8 on deeper-sdv07
Hello world from process 7 of 8 on deeper-sdv07
Hello world from process 3 of 8 on deeper-sdv05
Hello world from process 4 of 8 on deeper-sdv06
Hello world from process 0 of 8 on deeper-sdv04
Hello world from process 2 of 8 on deeper-sdv05
Hello world from process 5 of 8 on deeper-sdv06
Hello world from process 1 of 8 on deeper-sdv04

}}}
{{{#!comment
To use the SDV Cluster nodes (8 nodes) reserved for the DEEP-ER people (every day from 8:30am-5:00pm) please use:
{{{
qsub -q deeper-sdv -l nodes=X:ppn=Y:knl,walltime=...
}}}
}}}

When using a batch script, you have to adapt the --partition option within your script: --partition=sdv

== Filesystems and local storage ==

The home filesystems on the SDV are provided via GPFS/NFS and hence the same as on the DEEP System. 
The local storage system of the SDV running BeeGFS is available at 
{{{
/sdv-work
}}}

This is NOT the same storage being used on the DEEP-EST system. Both, the DEEP-EST System and the DEEP-ER SDV have their own local storage. On the DEEP-EST nodes it is
mounted to `/work` on the deeper-sdv nodes it can be found in `/sdv-work`. The DEEP-EST storage in `/work`can accessed, but with 1 GbE only. Hence, it should not be used for performance relevant applications since it is much slower than the local storages (see NVMe) and the DEEP-ER SDV storage (`/sdv-work`).


== Using /nvme ==
During job startup, all files of non-priviledged users within {{{/nvme}}} are removed. If you want to keep your files across consecutive jobs on a particular SDV node, add a list of filenames to {{{$HOME/.nvme_keep}}}:
{{{
/nvme/tmp/myfile.A
/nvme/tmp/myfile.B
}}}
This will keep the files {{{/nvme/tmp/myfile.{A,B} }}} across two or more job runs in a row.

== Multi-node Jobs ==
The SDV Cluster nodes are connected via EXTOLL tourmalet (100 Gb/s). 
Please use 
{{{
module load extoll
}}}
to run jobs on multiple nodes.