ARCHIVED: Libra usage policies

Note: UITS will retire Libra in spring 2009. Accounts are available on Quarry, a general-purpose Unix computing environment. For more, see ARCHIVED: About the Libra retirement.

On this page:

Accounts

As of February 16, 2009, new accounts on Libra are no longer available.

Home directories

Home directories reside on the EMC storage system and have a default and maximum quota of 1GB. Note that this space is shared with any files you may have in your Research Database Complex account. If you need additional permanent storage space, apply for an account on IU's Massive Data Storage Service (MDSS).

For more, see At IU, how much disk space is available to me on the research systems?

CPU limits and batch jobs

Interactive and background jobs are limited to 20 minutes of CPU time. Interactive and background jobs exceeding this limit are automatically terminated with no warning. If your job requires more than 20 minutes of CPU, submit it as a batch job to the IBM LoadLeveler queueing system using the llsubmit command. Jobs are assigned CPU limits depending on their batch class. The following batch classes (queues) are available:

  • Class serial: 1 CPU, < 2GB memory, 14-day wall clock time
  • Class nonshared: 1-2 CPUs, < 4GB memory, 14-day wall clock time
  • Class SMP: 1-16 CPUs, > 4GB memory, 14-day wall clock time

You may have up to eight batch jobs running simultaneously; additional jobs are left in the queue in a waiting state until the previous jobs finish. A fairshare policy for batch jobs is enforced, such that any user who is currently using or has recently used significant CPU resources will be given a lower dispatch priority than other users or groups submitting new jobs. The fairshare mechanism can also be used to give higher dispatch priority to users/groups for special research projects.

Mail usage

UITS does not provide a production mail service on the Libra cluster; however, LoadLeveler communicates via email. UITS recommends that you set up a .forward file for your Libra account. For help, see How do I forward my mail from a Unix account?

If you do leave your LoadLeveler e-mail messages on Libra, they may be purged. Twice per month /var/spool/mail is checked for mail files larger than 100KB. Files larger than that size are moved to /scr/mail. You may have up to two old mail files in /scr/mail. After a mail file is 30 days old it's purged from /scr/mail, as other files are from the local big scratch space.

Scheduled down time

The Libra cluster has a maintenance window on the first Tuesday of the month, 8am-5pm. If down time is necessary during this window or at other times, users will be given as much advance notice as possible.

Questions and comments

The policies described in this document were established with the goal of providing a stable, powerful, and efficient research computing environment for IU faculty, graduate students, and staff. If you have any questions or comments about these policies, UITS welcomes your input. Please contact High Performance Systems.