Just wanted to reply to say you're not the only one experiencing this! We've had to turn off all course backups just to ensure all the other adhoc tasks continue to run. Forum notifications were being delayed by days and the teachers were very unhappy. I fiddled around with the database to move the next backup date to very far in the future to prevent them from backing up (as the adhoc tasks had already been set up and were proceeding regardless of me telling the task not to run!).
I'm currently trying to see if there's another way to run the automated backups without letting Moodle do it itself. I might have to build a script that does the backups using MOOSH. It's a real pain!
I'll update you if and when I get any further.
All the best,
$CFG->task_concurrency_limit = array('core\task\course_backup_task'=>1);
If you combine this with the new task processing settings under: /admin/settings.php?section=taskprocessing , you can set "Scheduled task concurrency limit" and "Ad hoc task concurrency limit" to something higher than 1 (I've set 5) then it should only use 1 cron to run backups and the spare 4 to do all the other processing.
As I've got a large backlog of backups to run, I will fiddle around with the number of simultaneous backups so we can get some running in parallel - not too many though, to avoid thrashing the DB.
I found the information in this ticket, as well as a way of testing it, but it really ought to be documented in the main Moodle docs - or at least hinted at. https://tracker.moodle.org/browse/MDL-64610
So, to understand this better when you say that you have 5 crons you mean you have 5 servers running the Moodle cron or you start 5 instances of the cron at the same time?
If you mean 5 servers, this makes sense to me so 1 of the servers will be stuck running backups and other 4 will do other stuff.
If you mean 5 instances, could you please tell me how you achieve this?
Thank you once more for taking the time to share your finding Really appreciate it.