Nick Hill wrote:
I'm not sure how running two copies of MySQL on a machine is going to be faster than running one. Plus, I don't think MySQL can even work in this configuration.
I am not saying running two copies per se will be faster. Just that running a copy from a database file in ramdisk will be much faster. One instance of Mysql whose data file is on the mechanical disk, one instance being a replication slave whose data is on the ram disk. Data served from the ram disk, not the hard disk.
I think others have said this, but I think you're behind the times when you talk about a "ramdisk". We're not running DOS here. Linux will already cache as much as it can in memory, and in a sensible and automatic way.
But realistically speaking, this is not a bottleneck worth trying to solve. When it's working, the db server is very fast, and already holds everything that it needs in memory, as far as I know.
--Jimbo