-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Daniel Beckham wrote: > When someone says "I have a memcached hit ratio of 90%" they are talking > about a ratio (http://en.wikipedia.org/wiki/Ratio) as it relates to the > total amount of hits+misses: (get_misses / (get_hits+get_misses)) * > 100. e.g. If get_hits returns 900 and get_misses returns 100 we can > calculate the percentage of hits as related to the whole. > (900/(100+900)) * 100 = 90% of the memcached requests were hits. > Incidentally, this is a ratio of 9:1.
I've found that working with the "hits / hits + misses" ratio is counter-intuitive for people: for instance, the difference between 90% and 95% hit ration is *double* the load to the backing store. Therefore, when scaling a caching architecture, I nearly always talk about the "miss ratio" (10%, in the case above). Tres. - -- =================================================================== Tres Seaver +1 540-429-0999 [EMAIL PROTECTED] Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGkG2D+gerLs4ltQ4RAru3AJwOXTWqOg0Dnx77UPxgL8y8ih6WOACgjx6s c3h+AeDon3HszoBc00qZydg= =BdeO -----END PGP SIGNATURE-----
