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Posted to users@httpd.apache.org by Asrai khn <as...@gmail.com> on 2007/10/03 14:04:29 UTC

[users@httpd] Web server fail over setup

Hi list

I am looking for  what's the best failover setup for apache websever. We are
running apache web server with lot of virtual hosting. Sometime the servers
fail which also makes all sites hosting at that server unavailable.

So I am looking for suggestions how to make his failures of web server less
pain.

1. setup identical web server (do i have to use rysync to copy the contents
of one to another) ?

2. If the masters web server fails the slave automatically/or with less
hassle  take over all the traffic.


Regards. Askar

Re: [users@httpd] Web server fail over setup

Posted by Asrai khn <as...@gmail.com>.

On 10/3/07, Axel-Stéphane SMORGRAV <Ax...@europe.adp.com>
wrote:
>
> No matter which solution you choose, the real problem is to detect that
> the server fails.
>
> If the server stops responding to requests, that's easy enough. However if
> there is not a clear-cut failure, e.g. one server gradually slows down, or
> still responds to the polls from the load balancer but not to certain
> requests from clients the judgement call is harder...
>
> Apart from clustering solutions and HW load balancers, you could also add
> Apache 2.2 and mod_proxy_balancer to the list.
>
>
> Lot of suggestions are possible, but they all inflict pain.
> A very clean and widspread solution is to have two identical webservers
> (use a deployment script to keep the servers absolutely in sync) and use a
> hardware loadbalancer in front of the two servers. This is likely to cause
> financial pain.
>
> An alternative is to setup Linux HA-cluster. There are lot of how-tos
> around. Still the learning curve is so steep, it means pain. Not
> theoretically, but in practice, high-availability is only the goal. At
> first, it just hurts.
>
> You could also try to go with the most simple solution and make your
> server more stable. If you know you can cut your downtime by 50% by
> investing a week of work in the server, then this is probably worth it.
> Unless you need to cut it by 95% or 99%. But this would mean a lot of pain
> anyways.






Thanks guys for your valuable suggestions, as our web servers is hosted at
virtual machine (UML) in far data center it would be better to go for setup
identical VM in some other collocation and keep it sync (using rsync) with
the master and if master fails then switch to replica by doing little change
in DNS zone file to points the web server IP to replica.

Atm we are not looking for HA but fail over (even with some manual editing)
solution in case one collocation get down we can switch to other one with
little hassle and we can also afford 30 minutes down time :)

Thanks and regards. Askar

RE: [users@httpd] Web server fail over setup

Posted by Axel-Stéphane SMORGRAV <Ax...@europe.adp.com>.

No matter which solution you choose, the real problem is to detect that the server fails.

If the server stops responding to requests, that's easy enough. However if there is not a clear-cut failure, e.g. one server gradually slows down, or still responds to the polls from the load balancer but not to certain requests from clients the judgement call is harder...

Apart from clustering solutions and HW load balancers, you could also add Apache 2.2 and mod_proxy_balancer to the list.

-ascs

-----Message d'origine-----
De : Christian Folini [mailto:christian.folini@post.ch]
Envoyé : mercredi 3 octobre 2007 14:33
À : users@httpd.apache.org
Objet : Re: [users@httpd] Web server fail over setup

On Wed, Oct 03, 2007 at 05:04:29PM +0500, Asrai khn wrote:
> So I am looking for suggestions how to make his failures of web server
> less pain.

Lot of suggestions are possible, but they all inflict pain.
A very clean and widspread solution is to have two identical webservers (use a deployment script to keep the servers absolutely in sync) and use a hardware loadbalancer in front of the two servers. This is likely to cause financial pain.

An alternative is to setup Linux HA-cluster. There are lot of how-tos around. Still the learning curve is so steep, it means pain. Not theoretically, but in practice, high-availability is only the goal. At first, it just hurts.

You could also try to go with the most simple solution and make your server more stable. If you know you can cut your downtime by 50% by investing a week of work in the server, then this is probably worth it. Unless you need to cut it by 95% or 99%. But this would mean a lot of pain anyways.

regs,

Christian

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Re: [users@httpd] Web server fail over setup

Posted by Christian Folini <ch...@post.ch>.

On Wed, Oct 03, 2007 at 05:04:29PM +0500, Asrai khn wrote:
> So I am looking for suggestions how to make his failures of web server less
> pain.

Lot of suggestions are possible, but they all inflict pain. 
A very clean and widspread solution is to have two identical
webservers (use a deployment script to keep the servers
absolutely in sync) and use a hardware loadbalancer in front 
of the two servers. This is likely to cause financial pain.

An alternative is to setup Linux HA-cluster. There are
lot of how-tos around. Still the learning curve is so
steep, it means pain. Not theoretically, but in practice,
high-availability is only the goal. At first, it just
hurts.

You could also try to go with the most simple solution
and make your server more stable. If you know
you can cut your downtime by 50% by investing a week
of work in the server, then this is probably worth
it. Unless you need to cut it by 95% or 99%. But
this would mean a lot of pain anyways.

regs,

Christian

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