add exercise

_quarto.yml

@@ -56,7 +56,7 @@ website:
           - "exercises/git2/exercise.qmd"
           - "exercises/parallelism/parallelism.qmd"
           - "exercises/hardware/hardware.qmd"
-          # - "exercises/file_and_data_systems.qmd"
+          - "exercises/file-and-data-systems.qmd"
           # - "exercises/memory_hierarchies.qmd"
           # - "exercises/student_talks.qmd"
 

exercises/file-and-data-systems.qmd

+---
+title: "File and Data Systems"
+---
+
+Create
+
+* 10000 files of 1 MB each
+* 100 files of 100 MB each
+* 1 file of 10 000 MB
+
+in your `/scratch/` directory on levante.
+
+* Read them once and measure the durations for the read operations
+* Read every file 10x and measure the durations for the read operations
+* Repeat the read part of the exercise after a few hours.
+
+Discuss your results.
+
+Create a directory `/dev/shm/$USER` (replace `$USER` with your user ID) and repeat the exercise in there - you will probably need about 100 GB RAM to do this (or simply compute node) - no delayed repeat needed here (why?).
+