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> On Tue, 2003-07-22 at 03:32, Mark Watts wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > > On Mon, 2003-07-21 at 12:33, Jack Coates wrote: > > > > On Mon, 2003-07-21 at 12:17, Sevatio wrote: > > > > > What would I need to setup two Apache servers to serve the same > > > > > domain name using load balancing & round robin? Each user session > > > > > must be limited to one server. And it must be able to sense when > > > > > one of the servers are down and skip over that server to a working > > > > > server. > > > > > > > > http://www.foundrynetworks.com. > > > > > > > > If you can give up session persistence, LVS will do the job. Dude, > > > > looks like they've gotten persistence working! > > > > http://www.linuxvirtualserver.org/Joseph.Mack/HOWTO/LVS-HOWTO.persist > > > >ent_ connection.html > > > > > > further reading, it doesn't look so working after all. Cookies are > > > crucial to doing it right. > > > > Not at all... > > > > If you use ldirectord with heartbeat to control the load balancing, you > > just need to set persistent=120 (in the ldirectord.conf) to have a 2 > > minute persistancy window. > > > > Mark. > > That's fine if you're load-balancing for fault-tolerance; if you're > load-balancing for reasons of load, it doesn't scale because of proxy > servers, NAT, &c. You end up with bad balances, which is bad if one > server ends up handling more than 50% of its capacity. And how many > typical users are in and out of a site within two minutes, anyway? I > read that whole conversation about increasing memory utilization of the > LVS if persistence is kept too long. With RAM costing what it does these > days, just get a few gigs and be done with it. Why doesnt it scale? You don't have to do round-robin - there are several algorithms to choose from which give you different loading schemes. - From personal experiance, you simply don't notice the front end directors if you use reasonable kit. The bottleneck is all in the webserver(s). If you give the webservers more ram, they'll tend to cache stuff anyway so balancing the connections becomes less of a problem. When we hammered our HA search engine during performance testing, the director(s) didnt even bat an eyelid, and Apache on the webservers didn't really care to much either. We were mostly waiting on postgres... (Admitidly our directors were a pair of Dell PE1650's with 1.4Ghz P3 procs and 512MB ram, and the webservers are 2650's with dual 2Ghz Xeons) The 120 sec value for persistancy was an example anyway, you can use whatever you like. > > List price is $1000 per port for a hardware SLB with cookie persistence > support. If the money isn't there it isn't there, but a quick ebay shows > used Foundries going for $300 per port. What does cookie persistance do that LVS persistance doesn't? - -- Mark Watts Senior Systems Engineer QinetiQ TIM St Andrews Road, Malvern GPG Public Key ID: 455420ED -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE/HUpyBn4EFUVUIO0RAowEAJ4hjM9QumafNPCuzGnvMERnlmmxlwCgj6or NjJr3g5FRpvi5G3sm0vTWKU= =wyOJ -----END PGP SIGNATURE-----
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