Suggestion Required for VPS Hosting

[chadhaajay]

Hello,

This morning I received an email from our hosting service provider followed by a call from them. The essence of the email below:

today your site caused a huge spike in server load, it has happened before and we can't handle this load.
we suggest you move to a VPS or another host.
if you buy one of our packages a configuration charge applies.
this is very important so pleas respond.

I need your suggestions since there does not seem to be better place than webmaster world to ask this question.

1) What exactly is VPS hosting and how does it differ from the currently used shared hosting service.
2) What could be the reason of so called "huge spike" in server load with our website.
3) Would there be any impact (downtime, speed or other possible issues) on our website or traffic or search engine rankings during and after migration to the new server?

Thanks in advance,

Ajay Chadha

[edited by: phranque at 10:45 am (utc) on Mar 11, 2010]
[edit reason] url, email quote, hosting specifics [/edit]

[lammert]

1) VPS hosting is a type of hosting where a specific amount of memory, disk space and/or processor power has been assigned to you. These resources are used to build a virtual small computer inside a larger server. Such a virtual computer can run a large range of operating systems, mostly Windows or Linux and the Operating System itself is not aware of the fact that it isn't running on a physical computer, but inside a process which is running together with a lot of other isolated virtual servers on the same physical computer.

The good thing of VPS systems is that the hosting company can easily change the resources you are allowed to use, i.e. amount of diskspace, amount of RAM to be used etc. With shared hosting all processes eat from the same central memory, disk and CPU resources and if one process peaks in usage of CPU or memory, there is less left for the other processes. With a VPS this can be much better controlled.

2) The huge spike could have several reasons, including a visit of a scraper to your site, a periodic backup process which started or it could have been made up by the host just to force you in a more expensive hosting package to increase earnings.

3) If done right, there is only a little downtime involved and the search engines will pick up the new location of the site within hours, or maximum a day or so.

You should understand that a VPS is not the solution for all problems. In fact a shared server environment as you use now where your processes can use a large amount of RAM and have a large amount of CPU power available is much better in gracefully processing peak usage than a VPS where the amount of RAM is often limited to some low-end value like 512MB. With low memory availability your web processes will simply crash if they reach the upper memory limit. The hosting company won't complain, but you certainly will. Especially sites which do not have a smooth usage pattern can suffer from this.