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Book the testbed with OAR
Once you have accessed the testbed (i.e. connected on CorteXlab server), you can reserve the nodes for an experimentation.
To avoid cross interference between multiple experiments, only one person can use the whole CorteXlab testbed at a time. The OAR scheduler is used to book nodes on the platform. As soon as you book one or more nodes, the CorteXlab room is reserved for your usage during the requested time.
The state of reservation of the CorteXlab testbed can be visualized here: http://xp.cortexlab.fr/drawgantt/
The role of OAR is to schedule node reservations. It manages jobs associated with users. A job has a start time, a duration (walltime), and uses some resources (CorteXlab nodes).
The principle of operation of CorteXlab is that users submit jobs to OAR. When the job starts, the user gets exclusive access to the platform, and inside an OAR job, the user can perform (interactively, or in batch) one or several experiments.
A basic example to submit an OAR interactive job requesting all available nodes, for the default duration (which is 2 hours):
$ oarsub -I -l nodes=BEST
The same example with a max duration of 4 hours :
$ oarsub -I -l nodes=BEST,walltime=4:00:00
This command will wait for the resources to be available, and as soon as they are (i.e. -I stands for interactive), a job is allocated, is started, and a subshell is instantiated where you can work on experiments. As soon as the subshell is closed, the job ends. (It can be useful to work in a screen session to avoid losing jobs in case of network disconnection).
By default OAR submissions are scheduled as soon as possible. It is also possible to ask for an OAR reservation where you choose the date at which the job will be scheduled.
This other simple example is reserving all the nodes on the 18 of September 2015 from 10AM to 11AM:
$ oarsub -l nodes=BEST,walltime=1:00:00 -r "2015-09-18 10:00:00"
This command will wait for the resources to be available, and as soon as they are, a job is allocated, is started, and a subshell is instantiated where you can work on experiments. As soon as the subshell is closed, the job ends. (It can be useful to work in a screen session to avoid losing jobs in case of network disconnection).
By default OAR submissions are scheduled as soon as possible. It is also possible to ask for an OAR reservation where you choose the date at which the job will be scheduled.