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Getting Started - Discovering Queues


The first and ideal source for queue information and details about the queues on a cluster system should be your clusters support staff. They will be able to brief you on the details of particular queues, and their intended uses, and any limitations. If further information is needed you can use these commands to divine queue information from the scheduling system itself.


To view all the queues configured in your cluster system -

Example:

	
	[jdpoisso@umms-amino ~]$ qstat -Q     
	Queue              Max   Tot   Ena   Str   Que   Run   Hld   Wat   Trn   Ext T         
	----------------   ---   ---   ---   ---   ---   ---   ---   ---   ---   --- -         
	casp                 0     0   yes   yes     0     0     0     0     0     0 E         
	ambyroy              0     0   yes   yes     0     0     0     0     0     0 E         
	default              0   891   yes   yes     0   891     0     0     0     0 E         
	interactive          0     0   yes   yes     0     0     0     0     0     0 E         

	urgent               0   238   yes   yes     0   238     0     0     0     0 E         
	
	[jdpoisso@umms-amino ~]$


From this output we can see that the cluster umms-amino has five queues configured. It also lists out an overview of the queues, the number of jobs, the status of the queues, and the how many jobs are in various job states. With this information we get a basic summation of the activity on the system, and which queues are heavily in use.


For our purposes, the only important information are the names of the queues. The other information, though useful, does not tell us any specific details on what rules the queue uses. To do this, we need to run a ``qstat -Q -f'' on the queues.

Example:

	[jdpoisso@umms-amino ~]$ qstat -Q -f default 
	Queue: default 
	    queue_type = Execution 
	    Priority = 1 
	    total_jobs = 889 
	    state_count = Transit:0 Queued:0 Held:0 Waiting:0 Running:889 Exiting:0 
	    resources_default.nodes = 1 
	    resources_default.walltime = 01:00:00 
	    mtime = 1270501564 
	    resources_assigned.mem = 83886080000b 
	    resources_assigned.nodect = 889 
	    enabled = True 
	    started = True
	[jdpoisso@umms-amino ~]$



Using ``qstat -Q -f'' on the ``default'' queue, were able to see several pertinent details about the queue and the rules it uses. For instance we can see the ``Priority'' of the queue, which is a number assigned to all jobs submitted to the queue to determine when they should run. The higher ``Priority'' of your job, the sooner it will run. The other morsel of valuable information in are the lines regarding the default resources. this information you can see that each job submitted to this queue is given a single node by default, and a walltime of one hour. Note, these values are just defaults, meaning that your resource requests may override them. In this queue you will also notice there are no job minimums, and no job maximums, these will show up in this output if they are present. Also if there is a set amount of resources limited available to the queue, that also will be listed. (Draft Note: Construct an example)


Note: Not all queue rules may be listed in the output of ``qstat -Q -f'' especially for aspects like node restrictions, and whether the queue is limited to specific users. This is why first and foremost you should consult with your support staff or reference any cluster specific documentation for details regarding the queues.


next up previous contents
Next: Requesting Resources - Reference Up: Job submission - Requesting Previous: Job submission - Requesting   Contents
2010-08-27