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Important Changes for Allocation Year 2018

Note: Allocation Year 2017 (AY17) ends at 23:59:59 on Monday, January 8, 2018. AY18 starts on Tuesday, January 9, 2018 PST.

Cori and Edison Batch System Changes

Beginning in Allocation Year 2018 on January 9, 2018 NERSC is introducing a simplified batch submission scheme. Users need only specify a QOS (quality of service) in their batch scripts. SLURM scripts that specify a partition are deprecated and those that do will fail upon submission starting February 9, 2018. Current scripts will work until that time.

The changes will make batch submission simpler for users and improve the reliability and availability of the batch system.

QOS specifications

Below are the new allowed QOS values Note that "-q xxx" is the equivalent of "--qos xxx" starting January 9, 2018.

Current Scheme New Scheme Max Wall Time Submit Limit Run Limit Systems
<nothing> -q debug 30 min -- 2 Edison, Cori
-p regular -q regular 48 hrs --  -- Edison, Cori
-p regular --qos premium -q premium 48 hrs 5 -- Edison, Cori
-p shared -q shared 48 hrs 5,000 -- Edison, Cori
--qos=special -q special  special          special special Edison, Cori
-p realtime -q realtime custom custom custom Cori
--qos=interactive -q interactive 4 hrs -- 1 (max nodes per job = 64) Cori
-p xfer -q xfer 12 hrs -- 15  Edison, Cori
-p bigmem -q bigmem 72 hrs 5 Cori

Please note:

  • There are no longer premium shared jobs. 
  • A low charge class is not available. After a repository runs out of time, its jobs will be automatically eligible to run in the low-priority scavenger QOS.

Reservation Required for Modes Other than Quad,Cache on Cori KNL

All KNL nodes in Cori will be provisioned in Quad,Cache mode beginning January 9, 2018. Users who want to run in other KNL modes must request a reservation in advance. NERSC is requiring this because most codes run well in Quad,Cache and changing KNL modes requires a lengthy reboot that makes less compute time available to users.

At the start of AY18 on January 9, batch jobs still in the queue requesting any modes other than quad,cache will be removed, and new jobs requesting such will fail at submission.

Frequency of Programming Environment Software Default Changes

In oder to provide a predictable, stable and consistent programming environment while still making necessary software updates, NERSC will be updating the Cray Programming Environment and Intel's compilers on a set cadence. 

  • New software will be installed every 3 months, usually in December, March, September, and June. The new versions will not be made the defaults when installed. 
  • New software defaults will be set twice a year: Once in January at the Allocation Year Rollover (the previous year's September release) and once in June (the March release). The actual versions may vary subject to software verification and security or urgent fixes.
  • Only three CDT versions, the current default, the previous default, and the newest, will be made available on the system at any given time. If you need a CDT version that we have removed from the system, please contact consult at nersc.gov.   Note: Cray CDT (Cray Developer Toolkit) contains Programming Environment Software release including Cray compiling, message passing interface, performance, debugging, third party libraries, etc. Note some of the software packages may have more than three versions unintentionally. We will delete the extra versions in next maintenance. 

Cray’s module snapshot feature can help you to save the programming environment of your custom modules loaded and restore to use it later easily. 

Changes to How HPSS Mass Storage is Charged

Starting with the new allocation year, NERSC is changing the way it charge for tape archive storage on HPSS.  The old unit of SRUs were based on the consumption of a number of resources: data transferred, storage space used, and the number of files. The new charging scheme only considers the amount of data stored. We believe that this model will be simpler for users and easier for NERSC to manage.

Users who belong to multiple NERSC repositories will still see their archive usage spread between repos (this is adjustable via NIM) and PIs will still be able to adjust the relative percentage of archive quota each user can access via NIM. PIs will receive an email shortly with the values for their space allocation in the archive for the 2018 year.