VMware for Cyrus?

[Kenneth Marshall]

On Mon, Nov 09, 2009 at 02:35:53PM +0100, Sebastian Hagedorn wrote:
> --On 9. November 2009 14:10:54 +0100 Simon Matter <simon.matter at invoca.ch> 
> wrote:
>
>> While virtualization has advantages it has also disadvantages. One thing
>> is that it introduces an additional layer of complexity into the game.
>> It's my impression that in many areas virtualization gets introduced not
>> because of technical reasons but because of political pressure.
>
> In our case I wouldn't necessarily call it political pressure ... it's more 
> like organizational pressure. We have fewer personnel resources than we 
> used to, and have to run more systems with them!
>
>> For a high power, mission critical system like a mail cluster I'd stick
>> with real iron as long as possible. That may sound old fashioned but is
>> what I would do after everything I've seen. You will need the irons
>> anyway, with or without virtualization. Did I miss something?
>
> Maybe. Ideally you save irons by putting more than one VM on each. For the 
> mail cluster that may or may not be an option. I think it might, because as 
> I mentioned the current boxes are 5+ years old. So I'd think with brand new 
> hardware we would get away with less than 100% on each box.
>
> The main advantage that ESX would offer is in employing VMotion, VMMware HA 
> and such. It adds a layer of complexity, but also a layer of security and 
> convenience.
> -- 
>     .:.Sebastian Hagedorn - RZKR-R1 (Geb??ude 52), Zimmer 18.:.
>                 .:.Regionales Rechenzentrum (RRZK).:.
> .:.Universit??t zu K??ln / Cologne University - ??? +49-221-478-5587.:.

I will go ahead and chime in here. If and only if your I/O usage is
well understood and managed, would a VM option work. As others have
mentioned, any amount of heavy I/O will take out or slow dramatically
every VM that needs any I/O at all. Most people tend to over provision
CPU/memory on VM host boxes. Usually phrases like "it's all in memory",
"next to no I/O",... preceed the I/O backlog and consequent multi VM
outage. People really like their mail to stay up, maybe slow but up.

Regards,
Ken