Stuart, > I'm putting together a road map on how our systems can scale as our load > increases. As part of this, I need to look into setting up some fast > read only mirrors of our database. We should have more than enough RAM > to fit everything into memory. I would like to find out if I could > expect better performance by mounting the database from a RAM disk, or > if I would be better off keeping that RAM free and increasing the > effective_cache_size appropriately.
If you're accessing a dedicated, read-only system with a database small enough to fit in RAM, it'll all be cached there anyway, at least on Linux and BSD. You won't be gaining anything by creating a ramdisk. BTW, effective_cache_size doesn't determine the amount of caching done. It just informs the planner about how much db is likely to be cached. The actual caching is up to the OS/filesystem. -- --Josh Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
