Probably most of MySQL users sometime had a situation when they would do changes in MySQL config file without restarting server (may be matching SET GLOBAL command to do it in run time) but either because option is misspelled or because given version does not support such option the server when would refuse to start when it restarted, either on operating system restart or recovering from MySQL Server crash. In any case it is quite nasty.
Unlike Apache MySQL service control script does not have “configtest” option so there is no straight way to check MySQL config file for errors. However you can do it by running mysqld –help option:
[root@sl1 tmp]# /usr/libexec/mysqld --help
080212 12:39:30 [ERROR] /usr/libexec/mysqld: unknown variable 'myis_test=1'
This does not do complete check, ie it is possible to allocate 80GB to buffer pool instead of 8G you intended but at least it checks options for names which is good sanity check.
I would encourage you to run such check after you made changes to your config file for sanity purposes.