On Friday 13 December 2002 15:58, Paul Makepeace wrote: > Without going into lots of detail about what this is, since I'm trying > to be generic, has anyone here been involved with mod_perl sites that > do a substantial amount of full HTML page (i.e. non-banner-ad) > traffic? There'll be some SQL and Template Toolkit business going on > as well. I'm trying to nail down some capacity requirements which are > scaring me somewhat. > > The draft at the moment is wanting to support 2000 simultaneous users > with approx 1m page views/*hour* (300/s ish) i.e. each of those users > hitting about one page every six or seven seconds (by my calculations).
running ab against my random mod_perl stuff with TT and MySQL I have seen anyhting from 80 to 20 pages a second ... so lets guess on 30 .... > Is this totally insane? Or do-able? How much iron probably involved? so ... you'll need 10 cpus worth of mod_perl application servers .. a frontline of at least that number of client facing machines running as reverse proxies to allow the mod_perl engines to deliver a page to the proxy and get on with something else whilst the proxy handles delivery to the client. a load balancer and probably around about the same number of replaicated MySQL servers handing out data to the mod_perl app servers. (or some big Iron for the db backend) you will probably find that half a dozen mysql boxen are faster and cheaper than Big Iron) reverse proxies is the way to go on stuff like this as it allows the mod_perl stuff to run at maximum thrunge, delivering completed pages to thin and light client facing apache processes which can take their time pumping stuff out to clients. Caching may be a good plan too. Ebay do some heavy caching of snippets to cut out al lthe db queries when compiling lists of items for example. so .. say you go for 3U, dual processor machines. 5 for mod perl servers, 6 for client facing 5 mysql replicated dbs 1 master db 2 spares load balancer so 20 machines of 3U plus cooling space ... say 2 racks worth? plus UPS and routing, etc .. 2 and a half racks total? 3k a machine ... 60k .. plus bits routers, UPS, racks, spares, fans, shleves, cabling .. 100k total on hardware? > (Putting aside the unholy b/width requirements for now..) > > Just curious if anyone could handwave back... > > Paul off hand I'd say its bigger than most major sites Ive heard about (3 times CNN?) Id have to ask if your client had correctly calcultated the '2000 simutaeneous users' ... as thats a lot. -- Robin Szemeti
