into my backup Linux server (Ubuntu) I have done a system to backup my three servers. Into etc/crontab I have write line like this:
0 0 * * * user rdiff-backup -v9 user@111.111.111.111::/var/www/ /mnt/server1/www
0 1 * * * user rdiff-backup -v9 user@222.222.222.222::/var/www/ /mnt/server2/www
0 2 * * * user rdiff-backup -v9 user@333.333.333.333::/var/www/ /mnt/server3/www
But if the first rdiff-backup don't finish before 2:00 am, and the second rdiff-backup start is a problem? Can two or more rdiff-backup run together?