Scratch purging policy: Difference between revisions

Add instructions on how to safely copy symlinks out of scratch
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(Add instructions on how to safely copy symlinks out of scratch)
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=Abuse= <!--T:8-->
=Abuse= <!--T:8-->
This method of tracking file age does allow for potential abuse by periodically running a recursive <tt>touch</tt> command on your files to prevent them from being flagged for expiration. Compute Canada staff have methods for detecting this and similar tactics to circumvent the purging policy. Users who employ such techniques will be contacted and asked to modify their behaviour, in particular to move the "retouched" data from scratch to a more appropriate location.
This method of tracking file age does allow for potential abuse by periodically running a recursive <tt>touch</tt> command on your files to prevent them from being flagged for expiration. Compute Canada staff have methods for detecting this and similar tactics to circumvent the purging policy. Users who employ such techniques will be contacted and asked to modify their behaviour, in particular to move the "retouched" data from scratch to a more appropriate location.
=How to safely copy a directory with symlinks=
In most cases, <tt>cp</tt> or <tt>rsync</tt> will be sufficient to copy data from scratch to project. But if you have symbolic links in scratch, copying them will cause problems since they will still point to scratch. To avoid this, you can use <tt>tar</tt> to make an archive of your files on scratch, and extract this archive in your project. You can do this in one go:
<source lang="bash">
cd /scratch/.../your_data
mkdir project/.../your_data
tar cf - ./* | (cd /project/.../your_data && tar xf -)
</source>


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