Both sites are on the same server.
There is no info on the path or URL I need to supply for the CRON job to initiate the backups in any WP DB settings that I can see.
In my own plugins if I need a CRON job setup I will always say on the config page something like (from Strictly System Check) this...
To run this report you will need to setup either a CRON job on your server or if you don't have access to your server you can easily setup a WebCron job using one of the many free services available on the web.
Cron Command
*/20 * * * * /usr/bin/curl http://www.mysite.com/wp-content/plugins/strictly-system-check/strictly-system-check-reporter.php?code=2edeewe5911x___2a
WebCron Ready URL
And I find which program they have installed (WGET, CURL, LYNX etc) to use so I can show the correct path for a copy n paste.
However I see no mention of a cron job needing to be set here. So I am guessing the plugin SHOULD be setting an internal WP Cron job to be initiated by a page loading.
However for performance reasons - on both sites (same VS server) I have disabled the standard WP CRON URL that gets fired on every HTTP request (overkill) and instead setup a manual one that runs every 5 minutes instead.
So for both sites I have this set up in my CRON jobs on my server and the times are set for every 5 minutes. As I don't schedule posts or need WP to do its own jobs ALL the time as I have access to my server I just run it every 5 mins to run what WP needs e.g
wget -U StrictlyCron -q -O - http://www.mysite.com/wp-cron.php?doing_wp_cron >/dev/null 2>&1
I installed that WP Control plugin on both sites.
The site that isn't working shows a number of records but this is the only one that has a "delete" next to the end of it.
twicedaily 43200 (12 hours) Twice Daily Delete
However on the site that is working the same record is the only one with the delete next to it. However there are more options and it includes
dbmanager_optimize 172800 (2 days) WP-DBManager Optimize Schedule
dbmanager_backup 259200 (3 days) WP-DBManager Backup Schedule
dbmanager_repair 432000 (5 days) WP-DBManager Repair Schedule
jetpack_weekly 604800 (1 week) Jetpack weekly
Both sites use JetPack.
Whenever I save the settings I just get NA.
I don't know why the CRON is not being setup when I use the manage interface though. No error messages are returned which would be helpful to say why a cron job wasn't setup.
I guess I need to manually set these up if the plugin can't for some reason add the records to the database?