Interactive jobs

Recall the comments in Login nodes vs. compute nodes.

An example of getting an interactive session with 1 CPU core, 2GB of memory, for 2 hours:

qrsh -l h_data=2G,h_rt=2:00:00

Details:

  • By default, 1 CPU core is used.

  • There should be no space in between the items among the -l options. Adding spaces causes errors.

  • There will some wait time, especially when requesting longer time or a larger memory size.

  • When qrsh cannot be returned within a few minutes, try shorter time (e.g. 2 hours or less) and smaller memory amount, if applicable.

  • The interactive session returned by qrsh is a login shell, differnt from that of a batch submission (using qsub). Their differences is a common source of confusion. (A login shell is initialized differently from a non-login shell.)

  • Having a long qrsh session is possible but not recommended.

    • Long qrsh session is susceptible to interruption, which may terminate the session.

    • The wait time could be long (e.g. hours)

    • You could be “wasting” CPU time: occupying the CPUs and memory while idling.

    • If you plan to run long qrsh sessions, consider converting it to a batch submission.

More details about h_rt and h_data:

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Getting Started

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Time limit: h_rt