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)
| Purpose | Time limit specification (Slurm) |
|---|---|
| 10 minutes | 0-00:10:00 |
| 30 minutes | 0-00:30:00 |
| 1 hour | 0-01:00:00 |
| 12 hours | 0-12:00:00 |
| 1 day | 1-00:00:00 |
| 3 days | 3-00:00:00 |
| 1 week | 7-00:00:00 |
| 3 months | 90-00:00:00 |
