RE: Geographic loadbalancing

From: John Lauro <>
Date: Mon, 26 Jan 2009 11:38:28 -0500

I am not sure it would be called a bad idea, just not an effective one... don't expect it to help much when an ISP is down for only an hour. Most clients do not honor low TTL values, especially if they are revisiting the site without closing the browser.

I would like to hear anyone using anycast with TCP. What if two servers are equal distance. Wouldn't you have a fair chance of equal 50% packets going each way, killing tcp state connections. The more servers out there advertising the same IP, the more likely you will have cases of equal distance... or will packets typically go to the same server each time (or at least for several minutes) even if the costs are the same?

-----Original Message-----
From: [] On Behalf Of Tayssir John Gabbour
Sent: Monday, January 26, 2009 10:39 AM
Subject: Geographic loadbalancing


I'm considering geographically loadbalancing a website (where people order stuff) in case our ISP has a big network problem for an hour. Is this within HAProxy's scope?

A bit more context:

I'm told that anycast is the natural solution, but I find little on the net (or in books) on this. (Though there's more info on geodns, which I'm told is like a "poor man's anycast.")

I thought I could use a DNS server which polls server health (only serving addresses that are up), but I'm told this is a bad idea for reasons I don't yet grasp.

Any ideas?

Tayssir Received on 2009/01/26 17:38

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