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The status page at http://status.computecanada.ca/ is not updated automatically yet, so may lag in showing current status.
CC Clusters are vulnerable to the recent Meltdown/Spectre vulnerabilities, and will be updated, which involves updating the OS and CPU microcode. Read more at Meltdown and Spectre bugs.

Slurm can report: "Exceeded step memory limit at some point" which may be surprising and can cause a problem with dependent jobs.
- File I/O uses memory and Slurm is correctly reporting this usage. This usage (primarily delayed writes) was not as visible in previous systems. The kernel usually resolves such memory shortages by flushing writes to the filesystem.
- Memory shortage can cause the kernel to kill processes ("OOM kill"), which results in the same message but affects exit code differently.
- A job that reports DerivedExitStatus 0:125 indicates hitting the memory limit, but not being OOM-killed.
- Note that a step with 0:125 will *not* enable a job which has afterok dependency. This is a Slurm bug that will be fixed in 17.11.3, so that Slurm can distinguish between the warning condition versus actual kernel OOM-kill events. Slurm will continue to limit memory usage from cgroups, so I/O memory will still be counted and be reported when it exceeds the job's requested memory.

The CC Slurm configuration encourages whole-node jobs. When appropriate, users should request whole-node rather than per-core resources. Read about whole node scheduling.
By default, the job receives environment settings from the submitting shell. This can lead to irreproducible results if it's not what you expect. To force the job to run with a fresh-like login environment, you can submit with --export=none or add #SBATCH --export=NONE to your job script.

Nearline capabilities are not yet available; see https://docs.computecanada.ca/wiki/National_Data_Cyberinfrastructure for a brief description of the intended functionality.
- July 17 update: still not working. If you need your nearline RAC2017 quota, contact technical support.

Upon login to the new clusters, symbolic links are not always created in the user's account, as described in Project layout. If this is the case, please verify that your access to the cluster is enabled on this page https://ccdb.computecanada.ca/services/resources.

Nothing to report at this time.

Compute nodes cannot access Internet
- Solution: Contact technical support to request exceptions to be made; describe what you need to access and why.

Modules don't work for shells other than bash(sh) and tcsh.
- Workaround: (this appears to work but not tested extensively)
  - source $LMOD_PKG/init/zsh
  - source $LMOD_PKG/init/ksh