>>>> I ran into an out of memory problem. The first mention of it in the >>>> kernel log is "mysqld invoked oom-killer". I haven't run into this >>>> before. I do have a swap partition but I don't activate it based on >>>> something I read previously that I later found out was wrong so I >>>> suppose I should activate it. Is fstab the way to do that? I have a >>>> commented line in there for swap. ... > Switching from prefork to threads and vice versa can be very > difficult depending on which modules and libraries your site uses. It is not > on the list of things you should try first. Or second. Maybe 37th. > I wouldn't expect adding swap to do much in this case. Your site gets > hit hard, Mysql is a bit slow, Apache processes start stacking up, the > system starts swapping, disk is really slow compared to RAM, and everything > grinds to a complete halt possibly locking the machine up. > > The easiest thing to try is to turn off keepalives so child processes > aren't hanging around keeping connections up. Also lower the number of > Apache children to 8 * number of processors or a minimum of 32. Test a bit. > Turning off keep alive can cause problems for Flash based uploaders to your > site and code that expect the connection to stay up. For most sites this > shouldn't matter. > > Next I'd look at tuning your Mysql config. If you've never touched > my.cnf, by default it's set to use 64MB IIRC. You may need to raise this to > get better performance. key_buffer and innodb_buffer_pool_size are the only > two I'd modify without knowing more.
I use the default MyISAM tables and it looks like there are three key_buffer definitions in my.cnf. One under [mysqld] is 16M, one under [isamchk] is 20M, and one under [myisamchk] is 20M. All defaults. Should I increase them all to 64M? - Grant
