Experiencing partially degraded performance

Status page for the Harvard FAS Research Computing cluster and other resources.

Cluster Utilization (VPN and FASRC login required): Cannon | FASSE | Academic


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Monthly maintenance occurs on the first Monday of the month (except holidays).

GETTING HELP
https://docs.rc.fas.harvard.edu | https://portal.rc.fas.harvard.edu | Email: rchelp@rc.fas.harvard.edu

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Emergency maintenance 6/20/23 - Cannon Slurm Scheduler

Completed
Scheduled for June 20, 2023 at 11:00 AM – 1:16 AM

Affects

Cannon Cluster
SLURM Scheduler - Cannon
Cannon Compute Cluster (Holyoke)
Boston Compute Nodes
GPU nodes (Holyoke)
Kempner Cluster
Updates
  • Planned
    June 20, 2023 at 11:00 AM
    Planned
    June 20, 2023 at 11:00 AM

    WHAT
    Emergency Cannon cluster scheduler maintenance Tuesday June 20th from 7am - 11am (actual end time estimated). Running jobs will be paused during maintenance.

    Note: FASSE is unaffected by this.

    WHY
    As most of you know, there are on-going issues with the Cannon scheduler after the downtime and OS upgrades. This behavior did not show up in our earlier testing and only manifested once we were under load from user jobs again.

    After investigation we found that the scheduler is oscillating between two states every hour. During even hours the scheduler would enter a high thread state where all the traffic would pile up, causing any queries to either take a long time or time out. During odd hours the scheduler would enter a low thread state and operate normally. During periods where the scheduler is responding, jobs can be submitted and should then run normally.

    Unfortunately the root cause is still not known, and we are working closely with the vendor, SchedMD, to find a solution to return the cluster to stability. The version of slurm that we are running is 22.05.7, which while very stable — we have been running on it for the past 5 months with no problems — appears to be having issues at scale on Rocky 8.

    There is a newer version of the scheduler available, 23.02.3. This new version has a host of improvements. While the specific issue described above is not listed as one of the items fixed in this version, we anticipate that the upgrade may fix this issue owing to the various code improvements contained therein.

    Barring any solutions found over the long weekend, we intend to hold an emergency maintenance period on Tuesday June 20th starting at 7am. Running jobs will be paused. We will return Cannon to service as soon as we've completed work. Status of this maintenance will be tracked here on our status page.

    We thank you for your patience and understanding. Our team is hard at work answering your tickets and making sure that the cluster is back to full health. Also as a reminder that we hold additional Office Hours each week in June. See: https://www.rc.fas.harvard.edu/training/office-hours/

    FAS Research Computing
    https://www.rc.fas.harvard.edu/
    https://docs.rc.fas.harvard.edu/
    https://status.rc.fas.harvard.edu/

  • Completed
    June 20, 2023 at 1:16 AM
    Completed
    June 20, 2023 at 1:16 AM

    CANCELLED

    Emergency maintenance has has been cancelled. A solution to the scheduler issue has been found and Slurm is once again operating normally.

    We thank you for your patience and understanding.

For issues not shown here, please contact FASRC via
https://portal.rc.fas.harvard.edu or email rchelp@rc.fas.harvard.edu