Users can request a scheduled reservation of machine resources if their jobs have special needs that cannot be accommodated through the regular batch system. A reservation brings some portion of the machine to a specific user or project for an agreed upon duration. Typically this is used for interactive debugging at scale or real time processing linked to some experiment or event.
It is not intended to be used to guarantee fast throughput for production runs.
For normal batch jobs, charging against a project's allocation is done on a per job basis. For scheduled reservations the entire block of reserved time is charged regardless of the number of nodes used or time spent running jobs.
Requesting a reservation¶
To reserve compute nodes, a request must be sent in with at least 1 week notice. Please ask for the least amount of resources you need and try to schedule reservations so as to minimize impact on other users. It is also recommended that reservations be scheduled to start during NERSC business hours to ensure availability of staff in case any issues arise.
Cancellation of a reservation must be done with a minimum of 4 days notice. If you do not receive a confirmation that your cancellation was received and it is less than 4 days until your start time you must contact NERSC operations via 1-800-666-3772 (or 1-510-486-8600) menu option 1 to confirm.
To view all reservations run
scontrol show reservations, the output will consist of one entry per reservation name that can be used with option
--reservation to access the reservation. Take a close look at the reservation fields such as
to understand what the reservation.
$ scontrol show reservations ReservationName=knl_fp_test StartTime=2019-12-06T00:13:30 EndTime=2020-12-05T00:13:30 Duration=365-00:00:00 Nodes=nid10240 NodeCnt=1 CoreCnt=68 Features=(null) PartitionName=(null) Flags=SPEC_NODES TRES=cpu=272 Users=(null) Accounts=nstaff Licenses=(null) State=ACTIVE BurstBuffer=(null) Watts=n/a ReservationName=dvstrace StartTime=2020-05-05T16:23:01 EndTime=2021-05-05T16:23:01 Duration=365-00:00:00 Nodes=nid0[1571-1572] NodeCnt=2 CoreCnt=64 Features=haswell PartitionName=(null) Flags= TRES=cpu=128 Users=(null) Accounts=nstaff Licenses=(null) State=ACTIVE BurstBuffer=(null) Watts=n/a ReservationName=vESW_2020_Thurs StartTime=2020-06-04T09:00:00 EndTime=2020-06-04T12:00:00 Duration=03:00:00 Nodes=nid00[786-792,794-831,845-859] NodeCnt=60 CoreCnt=1920 Features=haswell PartitionName=regular_hsw Flags= TRES=cpu=3840 Users=(null) Accounts=ntrain Licenses=(null) State=INACTIVE BurstBuffer=(null) Watts=n/a ReservationName=vESW_2020_Fri StartTime=2020-06-05T09:00:00 EndTime=2020-06-05T12:00:00 Duration=03:00:00 Nodes=nid00[786-792,794-831,845-859] NodeCnt=60 CoreCnt=1920 Features=haswell PartitionName=regular_hsw Flags= TRES=cpu=3840 Users=(null) Accounts=ntrain Licenses=(null) State=INACTIVE BurstBuffer=(null) Watts=n/a
In order to use a reservation, the system administrators will grant access to individual users or by accounts. To filter by reservation name you can do one of the following
scontrol show reservations=<ReservationName> scontrol show reservations <ReservationName>
Shown below is a summary for reservation
$ scontrol show reservations=knl_fp_test ReservationName=knl_fp_test StartTime=2019-12-06T00:13:30 EndTime=2020-12-05T00:13:30 Duration=365-00:00:00 Nodes=nid10240 NodeCnt=1 CoreCnt=68 Features=(null) PartitionName=(null) Flags=SPEC_NODES TRES=cpu=272 Users=(null) Accounts=nstaff Licenses=(null) State=ACTIVE BurstBuffer=(null) Watts=n/a
knl_fp_test reservation is accessible to all users belonging to the
nstaff account because
Accounts=nstaff is set even though no users are defined
Users=(null). If you notice an error in your reservation, please reach out to us in order to make a correction. Take note of all fields listed in the reservation to ensure we have allocated the resources that matches your request.
Shown below we have a reservation
2005280700_TB_WS_HW_WORK assigned to user
tbrewer, however the reservation is no longer active since
$ scontrol show reservations 2005280700_TB_WS_HW_WORK ReservationName=2005280700_TB_WS_HW_WORK StartTime=2020-05-28T07:00:00 EndTime=2020-05-29T14:00:00 Duration=1-07:00:00 Nodes=nid0[0676-0679,1324-1327] NodeCnt=8 CoreCnt=256 Features=(null) PartitionName=(null) Flags=SPEC_NODES TRES=cpu=512 Users=tbrewer Accounts=(null) Licenses=(null) State=INACTIVE BurstBuffer=(null) Watts=n/a
Using a reservation¶
Once your reservation request is approved and a reservation is placed on the system, to run jobs in the reservation, you can use the
--reservation option on the command line:
nersc$ sbatch --reservation=<reservation_name>
nersc$ salloc --reservation=<reservation_name>
#SBATCH --reservation=<reservation_name> to your job script.
It is possible to submit jobs to a reservation once it is created - jobs will start immediately when the reservation is available.
KNL mode changes¶
KNL reboots can take up to 1 hour.
KNL nodes are configured as quad,cache by default. If you have requested a reservation with a different mode you will be responsible for rebooting the nodes into the proper mode and should account for this in your request.
Additional demonstration of need may be required for large scale reservations requesting reboots as system administrators are needed to assist in the reboot.
It is recommended to submit a "test" job at the start of your reservation to reboot the nodes.
cori$ sbatch -C knl,quad,flat --nodes=<size_of_reservation> --qos=regular --reservation=<reservation_name> --wrap="hostname"
If you forget to put the correct
-C option on all of your jobs you may lose 2 hours of your reservation to reboots.
Ending a reservation¶
All running jobs under a reservation will be terminated when the reservation ends. There are two ways to end a reservation earlier than scheduled:
When requesting the reservation, you can ask us to activate a setting that will terminate the reservation a few minutes after all jobs in the reservation queue have completed.
If your reservation does not have the above setting and you complete all planned computations before the reservation ends, please call NERSC operations at 1-800-666-3772 (or 1-510-486-8600) menu option 1 to cancel the reservation.