Then you either need to buy a prebuilt solution or get comfortable with the technology.
As I understand it you need; Two or more public IP addresses Load balancer Round robin DNS config Heartbeat software Enoguh hardware to make it work (extra NICs) You can do this with only the two servers you already have. Setup the IPs, one on each server. You'll need two more for mnanagement if you need to access these via Internet. Connect the second NIC on each box to each other via crossover cable and setup a private network. This link will act as a backup heartbeat in case a main NIC were to fail. I recommend red hat (or CentOS) cluster server software. It's got a pretty GUI but you will still need to know how it works. Here's the theory. If one server loses contact with the other (the heartbeat ping fails to respond) then the surviving server will take over the IP address of the failed server and will then handle the entire load. Since this means both IPs still work, the round robin DNS simply provides crude load balancing. Failback is usually best handled manually so it generally doesn't happen automatically. On a failover the clients that were connecting to the failed server will lose their session unless you have an independant and shared backing store. These clients would have to start over. This is but one topology for clustering that gives decent redundancy. There are still single points of failure (the same internet connection, switch, router, power circuit, etc). Sent from my BlackBerry device on the Rogers Wireless Network -----Original Message----- From: "Chuck Mariotti" <[EMAIL PROTECTED]> Date: Wed, 21 Mar 2007 07:19:54 To:<[email protected]> Subject: RE: [on-asterisk] Load Balancer? Needs to be session aware... other words, users stay on the server they first hit. If that server goes down, the load balancer detects and fails over to another web server (session lost). I would love to purchase an F5 but I think we're at a point where we shouldn't have to shell out major $ for something this simple. Round robin won't do... too much downtime and propagation issues that go with that. Regards, Chuck -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: March-21-07 5:35 AM To: [email protected] Subject: Re: [on-asterisk] Load Balancer? You're right. He really needs to define the needs better. Is this simple web serving or is there session information needed. Can the session information be stored centrally in a database. It may be that there isn't a simple answer. If sessions are needed then a layer 7 solution is needed like piranha and that means complexity or a hardware solution. Is no sessions are needed then DNS would be fine as long as the extra downtime is acceptable. Sent from my BlackBerry device on the Rogers Wireless Network -----Original Message----- From: Duane <[EMAIL PROTECTED]> Date: Wed, 21 Mar 2007 17:29:04 To:[email protected] Subject: Re: [on-asterisk] Load Balancer? [EMAIL PROTECTED] wrote: > That would achive load balancing, but you would have to have very short ttl's on your dns records. In other words if you have a 60 second ttl there will be users who cannot access a dead webserver until 1 minute after it's been found to be dead. Dead server detection would add more time to that as well. > > Now if you include cluster software that moves the ip address to a surviving server you've shortened the down time. His options are heavily dependent on his budget etc, and he asked about simple load balancing and DNS gives you this without the need for some very expensive hardware, or extensive knowledge on how to cluster boxes etc until the cost v benefit gets to the point that training and/or equipment purchases verses extremely high availability look like the better option. In the case of VoIP, SRV records are the recommended way to go in most cases as the clients (that can deal with them, and most seem to be able to) handle things much more gracefully. Without knowing more information I just offered the cheapest/easiest solution currently available. -- Best regards, Duane http://www.cacert.org - Free Security Certificates http://www.nodedb.com - Think globally, network locally http://www.sydneywireless.com - Telecommunications Freedom http://e164.org - Because e164.arpa is a tax on VoIP http://www.freeauth.org - Enterprise Two Factor Authentication "In the long run the pessimist may be proved right, but the optimist has a better time on the trip." --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
