Problem:
How do you adjust the walltime on all of the sub-elements of a job array?
Solution:
You can use mjobctl -m to modify the array, and ONLY provide the job ID for the base job, without brackets or additional indexing. That should apply the change to ALL of the elements of that job array.
Example:
[nburton@ibm08 ~]$ mjobctl -m reqawduration+=600 564
set walltime attribute for job 564 to '1:10:00'
set walltime attribute for job 564[1] to '1:10:00'
set walltime attribute for job 564[2] to '1:10:00'
set walltime attribute for job 564[3] to '1:10:00'
set walltime attribute for job 564[4] to '1:10:00'
set walltime attribute for job 564[5] to '1:10:00'
set walltime attribute for job 564[6] to '1:10:00'
set walltime attribute for job 564[7] to '1:10:00'
set walltime attribute for job 564[8] to '1:10:00'
set walltime attribute for job 564[9] to '1:10:00'