create lun to allow core dump

hi, we have a controller that keeps rebooting and it fails to write a log as the controller has no spare disks or it fails over too fast si i am lead to believe.  I am told I can create a lun for the file to be written to but i cant seem to find any specifics on what i need to create.  i understand what a lun is but when you create a lun you have to specify which os is to be used with etc etc.

when its say assign a lun is it referring to me presenting a lun to the actual controller, this would then appear in the array luns within oncommand system manager.  once the lun is seen by the system it can be just left as spare?

this is what i have referred to