Sebastian Hagedorn wrote: > --On 9. November 2009 14:10:54 +0100 Simon Matter > <simon.matter@xxxxxxxxx> 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. > I wanted to add a note here on this. We've been deploying ESXi where I work -- in some cases with success, such as development systems. We've noticed significant problems when it comes to disk I/O. Of course, our systems are RAID5 and that almost certainly contributes to it; though, I think you're going to see a performance hit either way. Anyone else care to comment on that issue? Best, Forrest ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
