[itdiscuss] A Thread about VMware

[Dan Barber]

Greg,
Hopefully this can help...I have been through VMware certification on 2.x, though not on the three, but the principles still remain the same. Feel free to call me and we can talk further.

1. By setup choices I am not sure what you mean. DNS name, IP address and such are one thing, partitioning is a whole 'nother thing. If you can be specific about what you would like to change I can help you out...

2. VirtualCenter has a special version for VMware Server that is about $1000. However, in my opinion, I might just buy the VC Foundation bundle from VMware for $3000 and then you get ESX 3.5 + support, and up to 3 ESX hosts (no VMotion). This is what we are running, and we converted from VMware Server on Windows. Much better performance and stability.

3. Memory assignment can be tricky. Yes, you can overcommit memory, and the ballon driver will take effect. However, the reality is that you don't need to assign as much RAM as you did in a physical box. Why? Because VMware dynamically shares identical bits of RAM between all running VMs on the same box. So, if you have 15 servers running Windows 2003 Enterprise, then it will only load the memory bits in common once for all machines. This gives you more efficient memory utilization based on the more identical the machines are on each box. So, I have two hosts with 16GB of RAM dedicated to Citrix, with 6 VMs on each host, all with the same OS. When I look at my performance, I am basically sharing 1GB of RAM between all the machines. So, here's how that would normally look:
        4 machines at 4GB/each = 16GB
        1 machines at 2GB/each = 2GB
        1 machine at 1GB/each = 1GB
        Total of 18GB of RAM needed for VMs, plus overhead for ESX.
But I don't have that...this works because what happens is the server dynamically maps the common bits. So, (though this is not quite accurate, you get the idea) this is how it works:
        4 machines are identical = 4GB of RAM
        1 machine is identical = 2GB of RAM
        1 machine is identical = 1GB of RAM
        User Memory specifics = 0-4GB of RAM
        Total of 6-10GB of RAM actually being used.

Right now as I look, though I have nearly 20GB of running machines, my server monitor says I am only using 6.53GB of actual RAM. That's how it works.

I hope this helps. Contact info below.

Dan Barber
314.434.0753

-----Original Message-----
From: discuss-bounces at itdiscuss.org [mailto:discuss-bounces at itdiscuss.org] On Behalf Of Greg Kern
Sent: Tuesday, February 26, 2008 8:53 AM
To: discuss at itdiscuss.org
Subject: Re: [itdiscuss] A Thread about VMware



I have a few more questions about VMware, if that's okay:

1.  Is there a way to VIEW -- and perhaps MODIFY -- the Setup
choices that were made when I installed ESX 3.0.1 on my Host
machine?  I realize this might involve a Reboot of the Host...

2.  Does the "VirtualCenter" that you can buy for VI3 work with
VMwareServer, and/or vice-versa?

3.  I've always assigned 2Gb, on average, to my VMs when I create
them, since this is the Memory I would want (if not more) in a
physical server... But the more I read about not "over-committing"
memory, and about how the sum of all memory cannot exceed what
the Host has to offer, and Balloon-drivers and such, I'm beginning
to think that this is too much... I realize I can make it, say,
512Mb and then just test performance, but, does anyone have any
thoughts on what, say, a Web server, or a run-of-the-mill Citrix
server should get?


Thanks very much you guys.
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