Specifying Job Time in Slurm

Overview

In Slurm, you need to specify the job time limit yourself.

• If you do not specify the time limit, i.e., if you do not write #SBATCH -t, Slurm treats the default time limit as 3 days.
• The maximum value that can be specified with -t (i.e., the execution time limit per partition) is 124 days. Please note this is 124 days, not 124 hours.

For long-running computations, please specify the time limit when submitting the batch job.

For details on how to specify the time limit, please refer to “Specifying Job Time in Slurm ” – “Details”.

Details

1. The time limit must be written in a fixed format

In Slurm, you cannot write the time limit freely.

Only the following format is available:

days-hours:minutes:seconds

No other format exists.

2. Meaning of each part (order is fixed)

days - hours : minutes : seconds

From left to right:

• days: how many days the job may run
• hours: how many hours
• minutes: how many minutes
• seconds: how many seconds

3. Only “days” can be omitted

3.1 Full format example

#SBATCH -t 3-12:34:56

Meaning:

3 days + 12 hours + 34 minutes + 56 seconds

3.2 Example omitting “days”

#SBATCH -t 12:34:56

Meaning:

12 hours + 34 minutes + 56 seconds

This does not mean “12 minutes”.

4. How to convert commonly used durations directly

4.1 10 minutes

Concept:

• days: 0
• hours: 0
• minutes: 10
• seconds: 0

Example:

#SBATCH -t 0-00:10:00

4.2 1 hour

• days: 0
• hours: 1
• minutes: 0
• seconds: 0

#SBATCH -t 0-01:00:00

4.3 3 days

• days: 3
• hours: 0
• minutes: 0
• seconds: 0

#SBATCH -t 3-00:00:00

4.4 1 week

1 week = 7 days

#SBATCH -t 7-00:00:00

4.5 3 months

Slurm does not understand “months”.

Always convert to days.

A safe beginner’s rule of thumb:

• 1 month = 30 days
• 3 months = 90 days

#SBATCH -t 90-00:00:00

5. Invalid examples (important)

5.1 Writing only minutes (invalid)

#SBATCH -t 10

❌ This will result in an error or be interpreted differently.

5.2 Writing “10:00” intending 10 minutes (actually 10 hours)

#SBATCH -t 10:00

❌ Slurm interprets this as:

10 hours + 0 minutes

5.3 Separating days and hours with colons (invalid)

#SBATCH -t 3:00:00:00

❌ This is not correct.

6. Copy-and-paste quick reference

Purpose Time limit specification (Slurm)