Policies

Policies concerning the usage of local computing resources

• The following rules are put in place to allow a fair share of resources between the users. In case you violate these rules your account could be disabled.
• In case you have specific needs concerning storage or CPU please contact the site administrators on T2bSupport.

User Interface policy

• All user interfaces are running Scientific Linux 6.
• The following machines are for light tasks, such as:
  • Crab submission
  • small interactive root processes
  • building code
  • debugging code

m0.iihe.ac.be, m1.iihe.ac.be, m2.iihe.ac.be, m3.iihe.ac.be

• The following machines are available for CPU-intensive and long tasks

m5.iihe.ac.be, m6.iihe.ac.be, m7.iihe.ac.be, m8.iihe.ac.be and m9.iihe.ac.be

This policy is enforced. Processes taking more than 10 minutes CPU on M1->M3 will be killed by the operating system. This limit is set to 5 hours on M5->M8. On M9 the limit is set to 500 hours

Disk space usage policy

• Users can have several locations to store their files/analysis code/final results/...
  • The /user partition on the UIs (m-machines) is limited to 500 GB per user.

    This space should be used as working environment, eg. to checkout code, store results,... It should not be used to store large datasets.

  • The /localgrid partition on the UIs (partition is mounted on the workernodes), with its quota shared with /user, so max(/localgrid + /user = 500 GB).

    This space serves as sandbox for input/output of jobs sent to the local batch queue.

  • The /pnfs area has a limit of 2TB per user.

    This area should contain the sometimes large dataset needed for physics analysis.

  • In case one needs more space, please contact the site admins here.

• Semi-Automatic removal of old files on /pnfs is done every 3 months.
  • All files not accessed in 1 year need to be explicitely un-flagged by the user in order to keep them
  • All other files CAN be marked by the user for deletion
  • Several mails will be send to remind all users to do this.
  • These mails will be send in a span of ~1month, after which the admins will proceed to the deletion of all flagged files.
• More information is found on the deletion page: http://mon.iihe.ac.be/OldPnfsFiles
  • If you need an account on this page, please ask the admins (grid_adminNOSPAM@listserv.vub.ac.be)

Back-up procedures of files

• The is a local backup (snapshot mechanism) of the user home directories (for more detailed info, see Backup
  • This back-up is made every day and we can go back day by day till last week. This is to address e.g. user small mistaken deletions.
  • Users are strongly advised to not solely rely on this backup. Using a versioning system (SVN or CVS) should prevent accidental removal of files and allowas a user to go back to a previous file when the file was messed up. We don't maintain a CVS repository ourselves but the CMS one should be used, more info here
• The entire user home directories are backed up every week in a physically separated hardware. This is to address catastrophe scenario.

Memory usage on the grid

• To protect the grid, there is an upper memory limit per job of 2.0GB (this is larger than what is asked by CMS) for the physical and the virtual memory.
• If your job exceeds this limit, it will be killed by the queueing system.
  • in you crab error log, you will find an error code 271
  • if you use direct submission, the reason will be clearly stated in your error log