1) Modern DBMSs cache database pages in their own buffer pool because it is less expensive than to access data from the OS. (IIRC, MySQL's MyISAM is the only one that relies on the FS cache, but a lot of MySQL sites use INNODB which has its own buffer pool)
2) Also, direct I/O is faster because it avoid double buffering. Rayson On 10/2/07, eric kustarz <[EMAIL PROTECTED]> wrote: > Not yet, see: > 6429855 Need way to tell ZFS that caching is a lost cause > > Is there a specific reason why you need to do the caching at the DB > level instead of the file system? I'm really curious as i've got > conflicting data on why people do this. If i get more data on real > reasons on why we shouldn't cache at the file system, then this could > get bumped up in my priority queue. > > eric > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
