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More on the HPC infrastructure#

Filesystems#

Multiple different shared filesystems are available on the HPC infrastructure, each with their own purpose. See section Where to store your data on the HPC for a list of available locations.

VO storage#

If you are a member of a (non-default) virtual organisation (VO), see section Virtual Organisations, you have access to additional directories (with more quota) on the data and scratch filesystems, which you can share with other members in the VO.

Quota#

Space is limited on the cluster's storage. To check your quota, see section Pre-defined quota.

To figure out where your quota is being spent, the du (isk sage) command can come in useful:

$ du -sh test
59M test

Do not (frequently) run du on directories where large amounts of data are stored, since that will:

  1. take a long time

  2. result in increased load on the shared storage since (the metadata of) every file in those directories will have to be inspected.

Modules#

Software is provided through so-called environment modules.

The most commonly used commands are:

  1. module avail: show all available modules

  2. module avail <software name>: show available modules for a specific software name

  3. module list: show list of loaded modules

  4. module load <module name>: load a particular module

More information is available in section Modules.

Using the clusters#

The use the clusters beyond the login node(s) which have limited resources, you should create job scripts and submit them to the clusters.

Detailed information is available in section submitting your job.

Exercises#

Create and submit a job script that computes the sum of 1-100 using Python, and prints the numbers to a unique output file in $VSC_SCRATCH.

Hint: python -c "print(sum(range(1, 101)))"

  • How many modules are available for Python version 3.6.4?
  • How many modules get loaded when you load the Python/3.6.4-intel-2018a module?
  • Which cluster modules are available?
  • What's the full path to your personal home/data/scratch directories?
  • Determine how large your personal directories are.
  • What's the difference between the size reported by du -sh $HOME and by ls -ld $HOME?