VMWare questions

[gaf-mNDKBlG2WHs at public.gmane.org (Jerry Feldman)]

On 12/06/2010 11:37 PM, Bill Bogstad wrote:
> On Fri, Dec 3, 2010 at 2:29 PM, Jerry Feldman <gaf-mNDKBlG2WHs at public.gmane.org> wrote:
>> Since we are on the subject of virtualization, I have a few questions.=

>> First, we have 5 Supermicro based servers each with 64GB of memory and=

>> Intel Woodcrest 2 dual core 2.66 GHz CPUs + 1 6U monster with 4
>> Woodcrest 3.4GHz CPUs. We are looking into a single VMWare server to
>> help and possibly begin to replace any server that dies. The new serve=
r
>> would have at minimum 2 Intel Nehalem 8 core CPUs (or AMD equivalent)
>> and 128GB memory. Storage is not an issue since most of the storage
>> would be from the NAS device, but the VMs and snapshots would be store=
d
>> locally. The type of work we do in our shop is financial modeling, or
>> running simulations on a number of financial instruments, which is ver=
y
>> memory intensive. Most of the VMs would be running RHEL 5.2 or later
>> with possibly a couple of Windows 7 or Windows 2008 server. Our IT
>> people are going to purchase and preconfigure the box with the latest
>> VMware bare metal product whatever they decide to call it. In any case=
,
>> my concern is with memory use. Some of the things we do, such as the
>> modeling is very memory and CPU intensive, and some things much less. =
I
>> don't want to have to configure each VM with a large amount of memory,=

>> but I would like it to be able to use additional available memory if
>> available (eg memory on demand). Some of the VMs would be somewhat
>> permanently running, and some would be brought up and down as needed. =
My
>> concern is that 128GB is too limiting, but I'm not sure at this point
>> even how the system will be used.
>>
>> The real question is can we configure a VMWare vSphere  VM to use
>> something like a range from something like 4GB to 64GB. And, if so, ca=
n
>> the VM that expanded return that back to the pool.
> Since no one else responded on list....
>
> I think the closest thing to this is memory overcommit and VMware's
> memory ballon driver which takes memory back from VMs without the
> guest OS having to be aware of the process.
>
> Here's one web page which discusses it briefly in the context of perfor=
mance:
>
> http://www.virtualinsanity.com/index.php/2010/02/19/performance-trouble=
shooting-vmware-vsphere-memory/
>
> I'm sure that you can get lots more info by looking up "ballon driver"
> on VMwares web site.
>
> Bill Bogstad
>
Thanks Bill,
This certainly answers the question. I'll make sure I pass it to our IT
guy in NY so when we do get our system we will have that option.

--=20
Jerry Feldman <gaf-mNDKBlG2WHs at public.gmane.org>
Boston Linux and Unix
PGP key id: 537C5846
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