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Queue | Partition | QOS setup on VSC-4
On VSC-4, Nodes of the same type of hardware are grouped to partitions. The quality of service (QOS), former called Queue defines the maximum run time of a job and the number and type of allocate-able nodes.
For submitting jobs to slurm, three parameters are important:
#SBATCH --account=xxxxxx #SBATCH --partition=skylake_xxxx #SBATCH --qos=xxxxx_xxxx
Notes:
- Core hours will be charged to the specified account.
- Account, partition, and qos have to fit together
- If the account is not given, the default account will be used.
- If partition and QOS are not given, default values are
skylake_0096for both.
Partitions
Nodes of the same type of hardware are grouped to partitions. There are three basic types of compute nodes, all with the same CPU, but with different amount of memory: 96 GB, 384 GB and 768 GB.
These are the partitions on VSC-4:
| Partition | Nodes | Architecture | CPU | Cores per CPU (physical/with HT) | GPU | RAM | Use |
|---|---|---|---|---|---|---|---|
| skylake_0096 | 702 | Intel | 2x Xeon Platinum 8174 | 24/48 | No | 96 GB | The default partition |
| skylake_0384 | 78 | Intel | 2x Xeon Platinum 8174 | 24/48 | No | 384 GB | High Memory partition |
| skylake_0768 | 12 | Intel | 2x Xeon Platinum 8174 | 24/48 | No | 768 GB | Higher Memory partition |
Type sinfo -o %P on any node to see all the available partitions.
For the sake of completeness there are internally used special partitions, that can not be selected manually:
| Partition | Description |
|---|---|
| login4 | login nodes, not an actual slurm partition |
| rackws4 | GUI login nodes, not an actual slurm partition |
| _jupyter | reserved for the jupyterhub |
Quality of service (QOS)
The QOS defines the maximum run time of a job and the number and type of allocate-able nodes.
The QOSs that are assigned to a specific user can be viewed with:
sacctmgr show user `id -u` withassoc format=user,defaultaccount,account,qos%40s,defaultqos%20s
All QOS usable are also shown right after login.
QOS, Partitions and Run time limits
The following QoS are available for all normal (=non private) projects:
| QOS name | Gives access to Partition | Hard run time limits | Description |
|---|---|---|---|
| skylake_0096 | skylake_0096 | 72h (3 days) | Default |
| skylake_0384 | skylake_0384 | 72h (3 days) | High Memory |
| skylake_0768 | skylake_0768 | 72h (3 days) | Higher Memory |
Idle QOS
If a project runs out of compute time, jobs of this project are now running with low job priority and reduced maximum run time limit in the idle QOS.
| QOS name | Gives access to Partition | Hard run time limits | Description |
|---|---|---|---|
| idle_0096 | skylake_0096 | 24h (1 day) | Projects out of compute time |
| idle_0384 | skylake_0384 | 24h (1 day) | Projects out of compute time |
| idle_0768 | skylake_0768 | 24h (1 day) | Projects out of compute time |
Devel QOS
The devel QOS gives fast feedback to the user when their job is running. Connect to the node where the actual job is running to directly monitor to check if the threads/processes are doing what you expect. We recommend this before sending the job to one of the compute queues.
| QOS name | Gives access to Partition | Hard run time limits |
|---|---|---|
| skylake_0096_devel | 5 nodes on skylake_0096 | 10min |
Private Projects
Private projects come with different QOS; nevertheless partition, QOS, and account have to fit together.
| QOS name | Gives access to Partition | Hard run time limits | |
|---|---|---|---|
| p….._0… | various | up to 240h (10 days) | private queues |
For submitting jobs to slurm, three parameters are important:
#SBATCH --account=pxxxxx #SBATCH --partition=skylake_xxxx #SBATCH --qos=pxxxx_xxxx
Run time
The QOS's run time limits can also be requested via the command
sacctmgr show qos format=name%20s,priority,grpnodes,maxwall,description%40s
If you know how long your job usually runs, you can set the run time limit in SLURM:
#SBATCH --time=<time>
Of course this has to be below the default QOS's run time limit. Your job might start earlier, which is nice; But after the specified time is elapsed, the job is killed!
Acceptable time formats include:
- “minutes”
- “minutes:seconds”
- “hours:minutes:seconds”
- “days-hours”
- “days-hours:minutes”
- “days-hours:minutes:seconds”.