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Storage

Two shared storage spaces are available on the CMAP workstations:

  • /home : safe, backed-up storage space. The disk space is limited. It must contain your sensitive, non-replayable data (manuscripts, codes,...). This directory must not contain large calculation results.
  • /home2 : Capacitive storage, unlimited, fast (10 Gbit/s link with the calculation machines). This storage is mainly intended to host your calculation results, data sets, ... You can ask for the creation of a personal directory /home2/users/login to the IT administrators. Warning, the data stored in this directory are not saved.

In some cases, you can also request temporary, unshared, and non-backuped storage space directly on a machine (in the form /users/login).

Some simple rules to remember:

  • before running a program with a "print" in an inner loop of depth 15, try to evaluate how many times it will pass through it.
  • the du command allows to know the size of the whole tree below the current directory.
  • du -s gives the same thing without the subdirectory details.
  • ls -lh allows to see the size of a file.

  • For those who are not too sure of themselves, it is possible to limit the size of the files you create:

  • for bash : edit the file ~/.bashrc and add the line ulimit -f 200000
  • for (t)csh : edit the file ~/.cshrc and add the line limit filesize 200000

You will not be able to create files larger than 200000 (200 MB)

  • Do not hesitate to compress little used files, especially result files or r-text files which have a high compressibility rate.
  • To compress 'toto' : gzip toto => toto.gz
  • To extract 'toto.gz' : gunzip toto.gz => toto

  • For large files of useless or unmanageable results, the rm command is even better :)

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