True, Moodle 2.4 doesn't include an admin/cli/backup.php script, but like I said (maybe not clearly enough or in a related post), one could acquire the code for a 2.7 or 2.8 in a test directory (via git right on the server), then copy the backup.php script to the older versions moodlecode/admin/cli/ directory.
Might work in 2.4 as long as all the files referenced in /backup/util/includes/backup_includes.php are present on the system.
Like I mentioned, does work in a 2.6 (and that didn't include the backup.php script either).
BTW, did run my experiment again ... with experimental turned on, the backup.php script did produce a smaller .mbz file - 14Gig -> 12Gig. But, still didn't complete the last step ... that of moving the file to the area for backups ... alternate directory IF running autobackups manually and designating a directory or in the back file area (which means filedir).
Definitely desire to keep that size of backup out of filedir ... that's a mess as it is now without adding to it.
IMHO, it sure would be nice for the true Admin user (user ID 1) to be the only one that could have access to a tool to at least help locate course backups in filedir and their sizes. Home grown script the only way right now.
Ran into a course from H---- not long back ago ... Digital Photography ... teacher backed up every week for a period of time due to assignments. Backup increased by about 1Gig after each assignment. Course finally reached limits and required manual manipulation.
Have a site from H---- right now that has several courses designed for the entire staff of a large school district - all teachers have accounts - and the courses are resources related to/and for teachers only. Massive amounts of PDF/Word Docs acquired from State Education Agency per grade level/subject. Each year they update those courses and rather than deleting links to older/out-of-date files (and the files to which they link), they hide them! So they have documents from the year 2012 still there that are no longer applicable. Easier to hide rather than delete ... so am told. Opps ... sorry, for soap box there ... my problem and just sharing that situation cause it's related.
'spirit of sharing', Ken