JoeB, Louis, Jamie, Vlad

This is an overdue log. 

The Cal group is moving away from using SVN as a version control tool for most of the Calibration group's code base and archival data. The files that the current SVN repository manages will remain but we're moving away from using SVN for version control. Scripts and other codes are going to be managed via git (https://git.ligo.org/Calibration/ifo). Data (regular calibration sweeps, one-off measurements, etc.) will be sync'd from the site CDS system to the site and CIT clusters using arx, an rsync-based tool maintained by Jamie Rollins. 

To begin facilitating this shift in librarianship, JoeB and I have implemented the following at both sites (workstation CDS), their respective clusters (ldas-pcdev1@ligo-{wa,la}), and the CIT cluster (as per the section documenting our discussion in T2200107.

- create arx directory in /ligo/groups/cal/{H1,L1}
- initialize the arx directory as an arx-managed target with endpoints to the corresponding locations on the remote clusters
- replace the following directories in /ligo/groups/cal/{H1,L1}/ with symlinks to the same inside arx/: measurements/, reports/
- from within the arx directory, push local files from the workstation to the site clusters: arx push .
- clean up pre-existing measurements/ and reports/ directories on the CIT cluster so that the sync scripts in ~cal/O4/ don't get confused by the new symlinks.

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There are more changes to come that will in effect (over time) obviate our need to use the files currently managed by the "CalSVN" SVN repo. These changes include copying data and source code from CalSVN into the new structure outlined in T2200107. Some of this work has also already begun; however no breaking changes have been introduced yet.