You can use a parameterized "format string" to systematically generate unique names for (usually) multiple I/O files, each of which receives some job I/O depending on the naming scheme that you choose. You can subdivide the received I/O into separate files by job ID, step ID, node (name or sequence number), or individual task. In each case, srun opens the appropriate number of files and associates each with the appropriate subset of tasks.
Available parameters with which to construct the format string, and thereby to split the I/O among separate files, include the following:
%J | (uppercase) Creates one file for each job ID/step ID combination for this running |
| job, and embeds jobid.stepid in each file’s name (for example, out%J |
| might yield files out4812.0, out4812.1, and so on). |
%j | Creates one file for each job ID, and embeds jobid in its name (for example, |
| job%j might yield file job4812). |
%s | Creates one file for each step ID, and embeds stepid in its name (for example, |
| step%s.out would yield files step0.out, step1.out, and so on). |
%N | Creates one file for each node on which this job runs, and embeds that node’s |
| short hostname in the file name (for example, node.%N might yield files |
| node.mcr347, node.mcr348, and so on). |
%n | Creates one file for each node on which this job runs, and embeds that node’s |
| numerical identifier relative to the job (where the each job’s first node is 0, then |
| 1, and so on) in the file name (for example, node%n would yield files node0, |
| node1, and so on). |
%t | Creates one file for each separate task in this running job, and embeds that |
| task’s numerical identifier relative to the job (the first task is 0) in the file |
| name (for example, |
|
For all format string parameters except the nonnumeric case of %N, you can insert an integer between the percent character and the letter (such as %3t) to
and
6.4.7 srun Constraint Options
The srun constraint options limit the nodes on which your job will execute to only those nodes having the properties (constraints) that you specify. The following constraints are available:
-C clist (--constraint=clist)
The
To conjoin (AND) multiple constraints, separate them in clist by using a comma (c1,c2).
To disjoin (OR) multiple constraints, separate them in clist by using a vertical bar (c3c4).
If no nodes have the feature(s) that you require with