[Dovecot] Virtual Servers

[Jonathan Tripathy]

On 28/06/2011 02:21, Jonathan Tripathy wrote:
>
>>
>> I hope this is a lightly used server and does not do any real level of
>> mail traffic else you'll soon regret running in any VM :)
>>
>>
> Don't mean to start a flame war, but your statement above is just 
> simply inaccurate. The main difference between a virtual server and a 
> physical server is that resources are contended with other VMs in the 
> virtual server suitation. So for example, if Dovecot required a lot of 
> resources, and there were another 1000 idle VMs on the same physical 
> box as the Dovecot VM, Dovecot would run fine. What is true for any 
> service (not just Dovecot) is that you need to get the balance right 
> depending on your server resources requirements and sharing the 
> physical resources with other VMs in such a way that you don't starve 
> some critical services.
>
> So please stop with the FUD about virtualisation :)
>
> BTW, I'm assuming a proper virtualisation solution such as Xen 
> Paravirtualisation.

I should also mention that I'm refering to VMs using direct block 
storage such as LVM, not VMs running off image files. Running anything 
off an image file is indeed going to slow your system down compared to a 
physical server.

A single VM system using file based storage is not going to beat a 
physical server. A single VM system running on direct block storage is 
going to be equal to a physical server in most respects. I'm not even
sure if VMWare support that to be honest, but Xen sure does. :)

IMO anyway..

Noel: I tried to reply to your email off list, but it bounced :(