5.1 Modifying the geometry of the pipeline

The current archiving system was designed so that removing or adding an archiver/miscellaneous process daemon to it should be fast and simple. Here is how to do it (let's recall that all the parfiles are in /archive/sw/par).

5.1.1 Removing an archiver/miscellaneous daemon from the pipeline

This is useful especially in case of an hardware problem from one of the devices. Here are the steps to follow:

• Shutdown the archive pipeline as explained in 3.2.1.
• Edit the master parfile archive.par and delete the entries corresponding to the daemon to be removed. Specifically:
• Remove the daemon's name from the daemon_names entry line;
• Remove the daemon's name from the arch_names or misc_names entry line (depending on the nature of the daemon);
• (optional) remove information on exefile, parfile, logfile for the daemon (these lines may be kept if the daemon may be reused later).
• Edit the distributor daemon parfile distd.par and delete the daemon working directory from the arch_dir or misc_dir entry line (depending on the nature of the daemon).
• Restart the archive pipeline as explained in 3.2.2

5.1.2 Adding an archiver/miscellaneous process daemon to the pipeline

This is for adding new functionnality to the archive pipeline.

If a new archiver is to be added, a media handler and a a media initializer must be written first, following the specifications set in 4.3.2 and 4.3.3. The executable for an archiver daemon can then be installed in /archive/sw/daemon just as a symbolic link to /archive/sw/daemon/archd.

If a new miscellaneous process is to be added, a new full daemon script must be written and installed in /archive/sw/daemon.

For both archivers and miscellaneous processes, a new parfile must be written to specify the parameters for the daemon (follow the existing ones as a guideline).

When all the new codes and parfiles are in place, the steps to follow are symmetrical to above and are as follows:

• Shutdown the archive pipeline as explained in 3.2.1.
• Edit the master parfile archive.par and add entries corresponding to the daemon to be removed. Specifically:
• Add the daemon's name to the daemon_names entry line;
• Add the daemon's name to the arch_names or misc_names entry line (depending on the nature of the daemon);
• Add information on exefile, parfile, logfile for the daemon in separated lines.
• Edit the distributor daemon parfile distd.par and add the path to the daemon working directory to the arch_dir or misc_dir entry line (depending on the nature of the daemon).
• Restart the archive pipeline as explained in 3.2.2