If you ever come across this error after having to do an emergency reformat of a server (ugh) it’s usually because the innodb settings changed in the my.cnf file.
The easy way to fix this is to delete your ib_logfile* files in /var/lib/mysql and restart mysql. It will recreate them and everything should work just fine and dandy again – at least well enough to dump tables and recreate.
This error can also be caused by a tmp directory with improper permissions.
Hopefully this will help someone.
