Comment 1 for bug 717256

I hit this bug too, but then realized it is an intended behavior. Since xtrabackup reads some of its options from my.cnf, it has to ignore all options it doesn't know.

On the other hand, silently ignoring typos in command line options is definitely not a good idea for a backup utility. I am not sure how this can be resolved. One idea is to parse my.cnf with a custom parser rather than my_getopt.