NSC Centre Storage policy

  • NSC Centre Storage is intended for storage of data associated with ongoing computing or analysis projects using NSC’s academic systems (currently Tetralith and Sigma).1
  • Storage is allocated to NAISS projects according to the NAISS storage policy.
  • Storage is limited both by volume (bytes), and number of files stored.2
  • Data that remains in a project directory after the project has ended will3 be deleted by NSC 90 days after the project ends. We will attempt to warn the project PI and all members that have stored data in the storage directory before this happens. 30 days after the project ends, the storage directory becomes read-only4. 60 days after the project ends, the storage directory will disappear from view. 90 days after the project ends, the data will be deleted. We will send weekly reminder emails to the project PI and all members (using the email address registered in SUPR) that have stored data in the storage directory for the first 60 days after the project ends.
  • Storage must be used efficiently and in a way that does not cause problems for NSC staff or other projects. This includes using suitable file formats, compressing data when appropriate, packaging data in archive formats (e.g tar, zip) when appropriate, … This also includes how applications perform I/O (e.g not doing unnecessary I/O or I/O patterns that cause problems for other users)
  • Projects that continue under another name can keep their storage directory name (/proj/projname), but the amount of data can be stored is determined by the new project’s allocation.

  1. Long-term storage is available on other systems, e.g Swestore. ↩

  2. There are two reasons to limit the number of files stored by a project. 1: certain operations, like checking/repairing the file system, and starting it after certain types of crashes, takes time proportional to the number of files in it. 2: every file, even empty ones, consumes a certain amount of storage space for metadata (filename, permissions, timestamps, …), which is not counted towards the normal quota. The files limit is currently not shown in NSC Express or SUPR. We will typically be generous when asked to raise this limit, it acts mostly as a tripwire to alert us to when a project starts storing data in a problematic way (millions of small files). ↩

  3. Currently, we delete the data manually at some point 90 or more days after the project ends. If you notice that your data is missing but there’s more than 90 days since the project ended, please get in touch with NSC ASAP, if you are really lucky we have not yet deleted the data. ↩

  4. Actually, the directory is not read-only, we set the quota to zero, which makes it impossible to write new data, but you can still delete data. You might call this “delete-only”. This makes it easier to move your data - you can delete files that have been moved and easily see what remains. ↩


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