RE: Geolocation Question

[Jon Keys <keyjc@xxxxxxxxxxx>]

Hi Karel,

Thanks for the reply ... I see your point about utilizing mod_proxy, but we actually use mod_status (which is preferred by mod_proxy_balance as far as I can tell) to feed mod_proxy_balance info for it's load balancing algorithms (bytes transferred, numbers of hits, etc...). Mod_status also allows the balancer manager to run which handles enabling / disabling of cluster members so we really have to use it. As for session management, we just want to redirect people back to the same server in case their download breaks or they want to download more than one file ... this way we can avoid the costly GeoIP lookup each time they return.

As a side note, I've been searching around on the ip2location forums and found that they have released an apache module which puts the ip2location data into  apache environment variables for each request. I think this would make a mod_proxy_balancer patch much more manageable but I'm not really sure? Is it generally easy to reference environment variables from modules? Also, I bought a book from Amazon called 'Writing Apache Modules with Perl and C' but it mainly focuses on Perl modules. Does anyone know how Perl modules stack up against C modules in terms of performance?

Thanks for replying,

Jon

---

> From: karel@xxxxxxxxxxxx
> Date: Mon, 18 Jun 2007 23:34:37 +0200
> To: users@xxxxxxxxxxxxxxxx
> Subject: Re:  Geolocation Question
> 
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> 
> Hi Jon,
> 
> Just my 2 cents - but I think Joshua has it right. If you're using  
> session management and weighted load balancing, then you must pass  
> the requests through your proxy - and hence your advantage of  
> geolocation is gone. If you're already using an external redirect,  
> then the proxy balancer has no way of knowing how many concurrent  
> connections worker is maintaining or how long they take or how much  
> bytes they serve (this would be needed for balancing purposes).
> 
> The only way I see it is to let mod_rewrite warp the browser to an  
> external url, e.g. from www.mysite.org to other domain names  
> (www.us.mysite.org, www.eu.mysite.org etc.) and then loose all  
> contact with the browser - which would mean to forget about sessions  
> and balancing.
> 
> Incidentally, if you have a good DNS provider or if you handle your  
> own DNS, then you could find a solution there - resolve  
> www.mysite.org depending on the requestor IP to a US-address, a EU- 
> address, and so on. An alternative approach, but I'm pretty sure that  
> this can work.
> 
> Hope this helps,
> Karel
> 
> On Jun 18, 2007, at 10:53 PM, Jon Keys wrote:
> 
> > Hey Joshua,
> >
> > You're right except we don't use mod_proxy_balancer in conjunction  
> > with mod_proxy ... we use mod_rewrite with '[R]' directive and  
> > point to the mod_proxy_balancer worker to determine which server to  
> > externally redirect to. Does this make sense?
> >
> > The reason we chose to do this was to take advantage of some of the  
> > nice features in mod_proxy_balancer (like session management,  
> > weighted load balancing, etc...). We are, however, not locked in to  
> > this solution. If something more efficient / easier to manage is  
> > out there we are definitely open to suggestions.
> >
> > Thanks for your reply,
> >
> > Jon
> >
> > > Date: Mon, 18 Jun 2007 16:10:50 -0400
> > > From: joshua@xxxxxxxx
> > > To: users@xxxxxxxxxxxxxxxx
> > > Subject: Re:  Geolocation Question
> > >
> > > On 6/18/07, Jon Keys <keyjc@xxxxxxxxxxx> wrote:
> > > >
> > > > Hi,
> > > >
> > > > I'm setting up some load balancing based on Apache with  
> > mod_proxy_balancer
> > > > and I'd like to incorporate geolocation based on IP address  
> > into the load
> > > > balancing algorithm.
> > > >
> > > > I know that IP's are not a reliable way of determining  
> > location, but we
> > > > purchased a package from ip2location to try and be as accurate  
> > as possible.
> > > > Even still, it's not perfect and that's OK because we are just  
> > distributing
> > > > the load of some free downloads ... if someone gets redirected  
> > to a server
> > > > that's not that close to them it won't be the end of the world.
> > > >
> > > > Anyway, does anyone know of such a patch / mod / plugin /  
> > application
> > > > compatible with apache2? If not, some pointers on where to  
> > begin developing
> > > > this would be greatly appreciated.
> > >
> > > Maybe I'm missing something, but this doesn't make any sense to me.
> > >
> > > If you are using mod_proxy_balancer, then all requests will go  
> > through
> > > the apache proxy server. That means there is no benefit in  
> > putting the
> > > back-end server close to the client. In fact, you want the back-end
> > > server close to the balancer.
> > >
> > > If you want the client to access stuff from a closer server, you
> > > should issue an external redirect. mod_rewrite would be a  
> > standard way
> > > to access a database to do a conditional redirect.
> > >
> > > Joshua.
> 
> 
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