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From Daniel Ruggeri <>
Subject Re: [users@httpd] Help regarding mod_proxy_balancer, failover and failonstatus
Date Mon, 18 Jun 2012 22:23:33 GMT
On 6/18/2012 3:17 PM, Praveen Baratam wrote:
> Can mod_proxy failover with out ever returning an error to the client?
> If active node fails I need mod_proxy to try the Standby for the same
> request and not just from the subsequent request!
> In our setup we are using mod_proxy_balancer to manage failover of
> backend servers. Backend servers may return an error code instead of
> timing out when some service such as NFS fails and we want such
> servers also to be marked as failed nodes. Hence we are using
> */failonstatus/* directive for the balancer.
> |<Proxy balancer://failover>
>     ProxySet failonstatus=503 
>     BalancerMember http://active/ retry=30
>     # the hot standby
>     BalancerMember http://standby/ status=+H retry=0
> </Proxy>
> |RewriteBase /
> RewriteRule ^(.*)$ balancer://failover/$1 [P,L]
> Currently the failover works perfectly with one glitch. When active
> node fails the user gets a 503 error and from the next request the
> Standby server takes over.
> I dont want even a single request to fail though. 
> Can this be achieved?
> Thank you!

   I'm afraid there are no provisions available to retry a request to
another backend server once it has been sent to a balancer member. I
would like to fix this some day but I am just not aware of a place that
this can be done currently as the balancer willy only attempt another
backend on connection failure only.

Daniel Ruggeri

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