Virtual server advice

We recently switched from a dedicated machine to a virtual one.
Now our Dedicated server had 1 Intel Xeon 3.2ghz CPU with 4 GB ram and normal 7200RPM WD harddisks.
The average load was around 0.8~2.

Now since yesterday we have moved our business to a Virtual Server environment (VMWare ESX) for better redundancy.
We have freshly installed a new Centos Enviroment on this VPS server.
We have 2GB ram, 80GB space (enough) and 1 virtual CPU.

The load now averages between 3 and 30.
It has become quite unstable and the websites on it respond too slow (3s for a pageload).
Now I'm wondering what causes this odd behavior.


Here is a copy of the "top" command

There are no processes which consistantly hog the CPU, rather just normal HTTPD threads like you'd see in normal operation. I also don't get the idea that RAM shortage is an issue here as there is little to no swap.
We are also not being limited in CPU usage by our VPS provider. (the virtual CPU should automatically adapt to how much we use and according to the hosting company the current server we run on has 70% idle cpu at almost any given time.)

Now one of the discussions I'm currently having with our hosting provider is IF enabling multiple virtual CPU's would increase performance and fix our load issues?and why)

so my questions are:

1. Are there any special steps one would need to take on a WMware hosted CentOS virtual environment which 'once neglected' could cause such issues as I describe?

2. Would enabling more virtual CPU's offer a solution (and more importantly .. why ?)

3. Are there any other things I should consider when running in a virtual environment?

 

Thank you both for your useful comments,
This does help get a better view on things.

I myself am familiar with Linux Environments on dedicated hardware solutions.
Though have worked a bit with VPS solutions i'm not familiar with the details.
What I do know is that a lot of companies do oversell their servers, I however do not think this is the case with the mentioned company.

The reason for the switch was mainly a decision from higher up.
I do know this new hosting company offers professional business solutions and their servers are equiped to handle high CPU usage (VMWare ESX cluster servers that are each 2x Quad Core XEON with around 32/48 GB of ram and a dedicated hardware RAID controllers).

One main advantage is increased redundancy, the setup the hosting company has is claimed to be far more redundant then our single-server setup. Since we have only a few servers we want to avoid having to go to the datacenter ourselves to fix server hardware issues.

I do not believe the company is overselling, they however have limited linux knowledge and the problem could perhaps lie in this fact. Do linux environments require special configuration on a VMWare setup ?

Our first intention is getting this issues resolved with the current hosting company before looking at alternatives.

I am however interested in knowing what (if they exist) redundant dedicated Hardware solutions there are out there that don't cost an arm and five legs.

 

A small update concerning the primary issues:

We have increased the number of virtual CPU's (total of 2) and added 1 GB ram.
It has been running a bit smoother but the load still tends to jump around. (though now not going above 8 at peak times)

I did ofcourse investigate beforehand came across various sources but none made the clear statement that it was strongly discouraged as a webhosting solution.

We have established a business relationship with this company (they actually reside 2 blocks over from here) and there is room for almost any improvement so if a dedicated server is truly the better option it is what we will end up getting.

I disagree, the previous environment on hardware failure would require us to go to the datacenter ourself and in case of motherboard failure tamper with the hardware risking hours of downtime (we owned the machine ourself).
Recovering cpanel backups (or rebuilding a RAID array) takes hours and having a machine on standby with all latest data is not an option either, nor is DNS-based solutions as almost all internet providers in The Netherlands ignore set TTLs and will still cache results for DAYS.

The current setup covers hardware and network failure where another VMWare ESX server would take over in case of 1 failing. So this would be an improvement, that is except for the load issues we are having.

They specialize in windows solutions, my personal impression has always been that installing a linux VPS only required a few OS optimizations specific to the Virtualization software the VPS runs on (Cpanel support claims something along the lines of this as well). As for management of the system I myself manage the OS environment, they manage the Virtual layers.

Thank you for the offer, though I cannot give you access to a production environment server, I would like to know what kind of optimizations you would consider specific to the VPS environment would these optimizations be more general OS-specifc or more VPS-specific ? (maybe an example?)

Always interesting to hear about various hosting solutions!
We have experimented with various methods but all seemed to have one or more drawbacks.
for example:

• DNS-based solutions are not an option since DNS-caching done by providers completely kills it.
• Server Rsyncing leads to strange and unwanted issues with different software versions (and sometimes fails to copy apply permissions).

Could you give a more concrete example of how the described setup would work?

Thanks again for the reply,
appreciate it!

 

Small update,
We installed 'VMWare tools' on the OS and enabled multiple virtual CPU's.
This does seem to take care of most of the issues!

It seems that VMWare has come along way in the past years and if your provider takes care with distributing the virtual servers then you should be okay with the virtual setup. (though a lot of providers WILL infact oversell their servers, but in terms of scalability and redundancy, virtual servers ARE the better option that is, IF it is configured correctly)

It would seem that linux needs to manage its own Threaded core balancing instead of VMWare (so you will need to enable 2~4 virtual cpus)