On Wed, Apr 11, 2012 at 07:18:18AM +0100, Bob Proulx wrote: > Karl E. Jorgensen wrote: > > Jumping back in (late) in this thread... > > Bob Proulx wrote: > > > > # free -m > > > > total used free shared buffers > > > > cached > > > > Mem: 7986 7913 73 0 224 > > > > 6133 > > > > -/+ buffers/cache: 1554 6431 > > > > Swap: 3813 0 3813 > > > > > > Shows 8G of ram. Good. Shows no swap used. Also good. (But not > > > necessarily bad if some swap is used. So if you see some swap being > > > used that isn't necessarily a problem.) > > > > Mostly good. Yes. But 6133 Mb Cached is not what I would expect - this > > indicates that the linux kernel is doing the caching - rather than > > MySQL. And the MySQL cache for this stuff is (almost) always more > > efficient. > > But at some point the daemon is going to need to write a file to disk. > That data will get cached at that time. Or are you saying that mysql > is using or should using O_DIRECT and avoid the cache explicitly?
No - although that might help (marginally) too. The point is that caching of data in MySQL will be more efficient than caching in the kernel disk cache; less layers and whatnot. -- Karl E. Jorgensen IT Operations -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20120411145523.GE30103@hawking
