Server Farms

[guest2013-1]

Hi guys,

I know how to setup/administrate a webserver (and mailserver) with ease, but I was thinking lately "How exactly does a server farm work?"

More-over specifically as to if I can get multiple sites to run off of this server farm....

For example:

I have 3 servers, they're in the farm (or you can call it a garden really). I have something like CPanel or Plesk, I then setup 10 domains on CPanel (or Plesk) and upload the files for my website and do all kinds of nice crazy things putting up websites and the like.

Now technically these 3 servers will then spread the load of these 10 domains across each other at peak times.

Now let's say one of them goes down. The other 2 still running perfectly takes over the load of the 3rd server that went down. I still have access to the sites via CPanel/Plesk as per normal until server 3 comes up again.

Is this viable/working or am I underestimating CPanel/Plesk and Server Farms? What needs to be setup to have a farm going?

Essentially I'm getting to this question:

Why is it that a host (shared) like Hostgator or Web Africa has 1 server with multiple domains on it, and if it goes down, so does all of those sites hosted on the 1 server... wouldn't it be better to set them up on a farm like Google has for their services?

 

[Archer]

To answer that last question, one word - money. Better failsafes will always cost more money. Simple as that

 

[djiceman]

You will need a load balancer connected to those 3 servers. This device will split the load as per configuration.

Load balancers are expensive, from $1500(rental) upwards. Theres alot more to this and it involves maintainence overheads and $$$

 

[texo]

Load balancing is the least of your challenges, and doesn't require expensive hardware, as there are some very good software solutions available. The challenge comes when you need to sync databases, sessions and so on.

 

[Conradl]

What you are referring to is Load balancing for high availability. To load balance a web site you require two copies of the site, each hosted on a different server - and thus two times the cost. Also,you would require some sort of load balancing mechanism to direct requests to the relevant host - DNS round robin will not work on the internet so you need another piece of hardware (the Citrix Netscaler can do this but it is pricey - its what google uses for their GSLB to direct requests across the world). This solution will share the load.

Another solution is to have a some sort of mirrored, redundant, solution, that will accept requests when the primary server stops working; this is also pricey but may or may not share the load....

 

[Conradl]

Load balancing is the least of your challenges, and doesn't require expensive hardware, as there are some very good software solutions available. The challenge comes when you need to sync databases, sessions and so on.

That's a good point to remember, most hosting packages have some sort of DB. Load balancing the front end will not help if the DB craps....

 

[RSkeens]

It would depend on your traffic, type of web site and the technical ability of the administrators. High availability is multiple more times expensive due to the extra servers involved and with base web hosting prices already pretty low compared to the high - end US market, etc. I don't see see them implementing it for shared server clients, unless they change their target market, which would be difficult locally.

It gets easier when you use virtualisation but you can still get a decently priced load balancer from reputable vendors. It really does all start adding up fast though.

 

[spiderz]

ubuntu cloud ... google it