[CentOS] OT: Why VM?

Fri May 27 22:41:03 UTC 2011
Rudi Ahlers <Rudi at SoftDux.com>

On Fri, May 27, 2011 at 11:54 PM, James B. Byrne <byrnejb at harte-lyne.ca>wrote:

> On Fri, May 27, 2011 14:36, Jack Bailey wrote:
> > There are lots of good reasons to virtualize.
> >
> > http://www.vmware.com/virtualization/why-virtualize.html
> >
> > Jack
> >
> As it turns out, that was one of the net resources I had in mind
> when I described what I found as mostly puff and smoke.  This is
> what this site claims as advantages to VM:
> > Top 5 Reasons to Adopt Virtualization Software
> >   1. Get more out of your existing resources: Pool common
> > infrastructure resources and break the legacy “one application
> > to one server” model with server consolidation.
> I have difficulty with this statement on so many levels that it is
> hard to know where to begin.  Perhaps the most egregious is the
> mindless equating of server with host.  What measurable benefits
> accrue to a firm from 'breaking the legacy', whatever that means.

It depends how you do this:

Many of our clients run SQL on a differen server than SMTP/IMAP/POP3 and
file & print sharing - thus 3 or 4 servers. Now they can deploy 1 large
server and run everying on different VM's - they still get the same security
and isolation, but save some cost.

OR, they can have 2 servers with a shared SAN and have everything running on
those 2 servers and have high availability. Something they probably didn't
in the past in any case.

> >   2. Reduce data center costs by reducing your physical
> > infrastructure and improving your server to admin ratio:
> > Fewer servers and related IT hardware means reduced real
> > estate and reduced power and cooling requirements. Better
> > management tools let you improve your server to admin ratio
> > so personnel requirements are reduced as well.
> Personally, my experience is that, if anything, running multiple
> systems on a vm host measurably increases the administrative burden
> per host.  For one thing, you now have multiple instances to update
> and to keep secure whereas before you had one OS to worry about.  If
> we had tens or hundreds or thousands of servers then yes, I can see
> the benefits.  We, however, do not deal with equipment on that
> scale.

Again, this is about saving hardware, power, heat and storage. One could
very easily replace a rack full of servers with just 3 or 4, or so and thus
be more green - save some space, power and heat.
Effectively you still have the same amount of OS / applications to run, but
you're using less hardware

> >   3. Increase availability of hardware and applications for
> > improved business continuity: Securely backup and migrate
> > entire virtual environments with no interruption in service.
> > Eliminate planned downtime and recover immediately from
> > unplanned issues.
> I suppose that moving VM instances as file systems provides a real
> value by eliminating the setup and configuration required to get
> bare metal to flash up in a usable fashion.  This is in fact the
> only area that I see a real advantage to VM over bare metal
> installs.
> >   4. Gain operational flexibility: Respond to market changes with
> > dynamic resource management, faster server provisioning and
> > improved desktop and application deployment.
> I have no idea how deploying VMs to a company's desktop workstations
> could possibly benefit the firm.,

I can provision a new VM to a client withing minutes. A server takes more
like an 30minutes to an hour to get up and running.

> >   5. Improve desktop manageability and security: Deploy, manage
> > and monitor secure desktop environments that users can access
> > locally or remotely, with or without a network connection, on
> > almost any standard desktop, laptop or tablet PC.
> Again, how is this accomplished and what are the advantages over a
> single OS install?  None of the above claims have anything to do
> with VM per se as far as I can see.

Well, each end user desktop could be saved as a VM to make re-installation,
or "uprgrades" much easier.

> --
> ***          E-Mail is NOT a SECURE channel          ***
> James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
> Harte & Lyne Limited          http://www.harte-lyne.ca
> 9 Brockley Drive              vox: +1 905 561 1241
> Hamilton, Ontario             fax: +1 905 561 0757
> Canada  L8E 3C3
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos

Kind Regards
Rudi Ahlers

Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.centos.org/pipermail/centos/attachments/20110528/557feec0/attachment-0005.html>