$CFG->mod_hvp_backup_libraries is undocumented

[marxjohnson]

We have a client who is concerned that courses with instances of mod_hvp are taking a very long time to backup, sometimes resulting in timeouts from the load balancer.

Looking in to this we found this was due to the inclusion of all H5P libraries in the backup, not just those used on the course. As the site is using ObjectFS, this added the latency of downloading several thousand small files from object storage to the backup task.

It appears that the solution to this is to set $CFG->mod_hvp_backup_libraries = 0; in config.php. I was only able to find this by looking at the code, and there is no explanation of the risks or limitations associated with excluding libraries from backups.

Please could you add some documentation to explain this setting, allowing for informed decisions about whether to use it?

[nadavkav]

We use this too, and also found it while looking in the code for a solution to the hague backup files and slow backup process.
We turn it ON when doing a course backup with H5P activities that we need to transfer to a different Moodle site, otherwise, it will not work.

[danowar2k]

Another way one can ensure working activities when backing up/restoring to a different site is to upgrade all used libraries (and the activities using them) on the old site, install and upgrade all libraries on the new site and only then backup and restore the activities.

Since you can't install older library versions on the new site, you can either do that or live with turning on the slow library backup feature.

[danowar2k]

Reference: #561