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Re: linux friendly hardware inquiry/advise

On Wed, 19 Oct 2011 19:05:00 -0500, Stan Hoeppner wrote:

> On 10/19/2011 11:28 AM, Camaleón wrote:
>> On Wed, 19 Oct 2011 22:24:37 +1000, yudi v wrote:
>>> Building a new PC, will be used for coding mostly, running 2-3 VMs
>>> simultaneously.
>> Then -although you have not say any specific number- add more ram (8 up
>> to 24 GiB is a good starting point) ;-P
> 8-24GB?  For a development box running 2-3 VMs?  That's overkill.  Let
> me explain.


Okay, Stan... I agree -to some extent- with your explanation, but didn't 
you notice the emoticon I put at the end of the paragraph?

(Tip: ";-P")

I wanted to put emphasis in memory because of the nature of the computer 
that will be used to run virtual machines and for coding (which lead me 
to think also in the needing of compiling stuff).

I agree that a 24 GiB box can be overkill "now", but in about 5 years it 
can become a common amount of ram on standard (non specific purpose) 

> At a previous $day_job a few years back we were running a mix of 13 SLES
> 9/10, W2K3, and Sarge VM guests across two dual CPU dual core Opteron
> 2GHz IBM blades (4 cores/blade) with VMware ESX3.  Each blade had "only"
> 8GB RAM.  Additionally, were were running the 32 bit VMware kernel with
> PAE as the native 64bit kernel wasn't available yet.  All the VMs were
> 32bit as well.


That were high-end machines running on a virtaulization system which does 
a very good management of the host resources, which is focused to the 
enterprise market and runs over no OS layer but directly on a bare-system.

Besides, you know that VMWare provides a detailed hardware KB where lists 
all of the supported/well tested hardware where it can be run and you 
know that you are not going to get the same level of performance running 
VMware ESX3 over IBM blade systems with Opterons as with a 150$ 

That said, I use VirtualBox on my notebook (a windows xp based host with  
one centrino core and 4 GiB of ram) and can only launch a virtual machine 
at a time (debian testing and debian stable are the guests with ~1 GiB of 
ram for each). Launching two VMs will, of course, decrease noticiably the 
host performance and makes one of the VMs to pause. I can reduce the 
memory available to the guests but then GNOME becomes a bit slow.

> With or without using KSM
> (http://www.kernel.org/doc/Documentation/vm/ksm.txt), Yudi should be
> able get by easily with 4GB of RAM. As memory is so cheap these days he
> may as well get 8GB.  Anything over that is money wasted, no matter how
> little, on simply having more buffer cache.  If we were runing 13 VMs in
> 8GB, surely he can run 3 in 4GB.

Of course, the election of the VM system and the applications which are 
going to be hosted on it do matter a lot, but more details are needed  
before making further recommendations on this.



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