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Directory /dcache (Stoomboot)

Aim: Describe the Stoomboot dCache storage.

Target audience: Users who want to store large amounts of data at Nikhef.


The dCache store can hold your largest data files. It’s a distributed storage system, designed to cope with the load of Stoomboot running on all cylinders (or nodes, in this case). Access looks like a normal file system (/dcache/...), but once written a file cannot be modified - only re-written in full. It’s the perfect place for analysis results, your ntuples, and MC samples.


Intended use

Large scale data files, files access from many (Stoomboot) systems at once

Examples of data types that are better put elsewhere

  • your software and scripts (these should be in /project or your home directory);
  • intermediate log files (these should be in $TMPDIR or /localstore).

What are the limitations?

This filesystem is not backed up, so if the system fails catastrophically: too bad. You will have to re-create or re-download the data. Also, dCache files cannot be modified (or appended to), and are written ‘in one go’, but it still looks like a regular filesystem. Out of space? Ask your group leader to discuss with the CT-PDP team.

Did you know...

Did you know that files in dCache can also be read remotely through the GridFTP, WebDAV, and xrootd protocols? Register your certificate distinguished name for access.