Re: priority servers in an instance

From: Willy Tarreau <>
Date: Sun, 22 Feb 2009 21:00:45 +0100

On Sun, Feb 22, 2009 at 10:03:22AM -0800, Michael Fortson wrote:
> That's really cool. I've been doing it with weighting, but this is much
> nicer.

it was proposed and developped by someone on the list (I don't remember whom right now) for exactly this purpose.

> Am I right in assuming that in this example, when nearly_full is triggered,
> it will switch entirely to that?

yes, back1 will get traffic only when it's not considered full, and back2 will get the excess traffic.

> how does the balance between the two
> backends happen in this instance?

There's no balance. The second backend only receives overloads. See that as a cheap vs expensive pool of servers (or local vs remote).

> Should you just repeat the definition of
> the first backend within the second to go "wide" with the server spread?

Yes, this seems appropriate depending on your workload. Maybe you'll remove "maxqueue" from the second though.

Hoping this helps,
Willy Received on 2009/02/22 21:00

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