Overselling

[TechFox]

Can anyone explain web hosting overselling in laymens terms?

 

[desk2web]

Hi, as I understand it, its selling too many slots on a server, or having toom many sites on a single pipe, so that if all the sites, or many of the sites, were being accessed at the same time the entire network slows or fails (in extreme circumstances).

Its a bit like having a balloon filled with water, pierce the balloon in one place and the water comes out strongly, pierce it in several places and the pressure is spread, therefore lessened at each hole - and you end up with water all over you! Hope that analagy makes some sort of sense?

OK, now those of you who actually know the answer, or who have researched google can post the "proper" answer, but this is what it means to me.

See ya

Allan

 

[DuaneJackson]

The analogy totally lost me, but in essence you're right.

Some companies will put thousands of website on one physical server, which has a negative impact on it's performance.

Obviously each server costs the company money so they are trying to squeeze as much profit out of it as they can at the expense of the hosting customer.

 

I've always thought overselling as advertising something that they don't have the resources for i.e. giving a hosting plan with "unlimited" bandwidth and they don't even have it available. :wink:

 

[TechFox]

Thank you for that

 

[DJHunter]

I'm still lost, can anyone break this down?

 

[robertt]

Overselling can be when a company sells 100 accounts with 1 gigabyte of disk space, ie. 100gig total, but then put them on a server with an 80gig hard drive. Thus a 20gig shortage.

The theory being that not everyone uses 100% of their quota

There was a defence of this by Dreamhost recently who stated that the hosting industry is like a Gym. There may be 10,000 gym members but only 1000 bits of equipment... so if everyone turned up at once things would become messy.

Overselling can be seen as dodgy, however if its balanced correctly (ala the Gym analogy) it can work ok.

 

[TechFox]

Overselling means cramming too many sites onto a server so that if too many of the sites are accessed at the same time the entire network slows or, in extreme circumstances, fails. Hosts that oversell save costs which allows them to charge lower prices, but the service they provide can be unreliable.

 

[SuffolkDesigns]

Overselling is basically selling more resources that are actually available based on the assumption that people will not use 100% of what they have bought.

Alot of different businesses oversell including telecommunications (imagine if everyone made a mobile telephone call at the same time)

It does not mean cramming too many sites on a server, a server should be monitored based on a number of variables. A server with 2000 small unused websites will work alot better than one with 2 really busy huge sites on it.
Also, having alot of sites on the same server accessed at the same time does not affect the network at all, it affects the memory and cpu usage slowing down the server as well as possibly affecting other services such as sql and mail.

Hosts that oversell (I don't but I charge more ) are not neccesarily unreliable as long as the overselling is controlled.

 

[SuffolkDesigns]

btw, as a **host** yourself I am totally amazed that you asked this question.

 

[DuaneJackson]

btw, as a **host** yourself I am totally amazed that you asked this question.

and answered it too. odder and odder.

 

[KM-Tiger]

An extreme case was someone selling hosting on the end of a domestic ADSL line! The site seems to have gone now, but it was discussed at length here:-

http://bbs.adslguide.org.uk/showflat.php?Cat=&Board=plusnet&Number=2495980&page=&view=&sb=&o=&vc=1

There's no-one called Sharky here is there?

 

[SuffolkDesigns]

An extreme case was someone selling hosting on the end of a domestic ADSL line! The site seems to have gone now, but it was discussed at length here:-

http://bbs.adslguide.org.uk/showflat.php?Cat=&Board=plusnet&Number=2495980&page=&view=&sb=&o=&vc=1

There's no-one called Sharky here is there?

That is more common than most people would think

 

[Toon]

i took it to mean that if a server could handle 200gig of bandwidth (for example) and would then create 5 accounts with 45gig bandwidth. The host presumes that not all of the sites would reach their allowance 100% each month and therefore even though he has sold 225gig he would only expect to use less than 200gig. If it did start to approach 200gig each month then he could just upgrade the server or split the accounts onto two different servers.

 

[SuffolkDesigns]

i took it to mean that if a server could handle 200gig of bandwidth (for example) and would then create 5 accounts with 45gig bandwidth. The host presumes that not all of the sites would reach their allowance 100% each month and therefore even though he has sold 225gig he would only expect to use less than 200gig. If it did start to approach 200gig each month then he could just upgrade the server or split the accounts onto two different servers.

Overselling bandwidth is a very different issue to overselling disk space, especially where server reliability is concerned. A decent server can chuck out alot of bandwidth if the data it is processing is simple html pages. for example a 1mb image can be served quite easily many of hundreds of thousands of times per month. Whereas a few sites using less bandwidth can cause alot of server failures because they are using complax database procedures.

 

[SuffolkDesigns]

and answered it too. odder and odder.

Yup, but the answer was totally wrong, which did not surprise me.....