[linux-elitists] Virtualization

Karsten M. Self kmself@ix.netcom.com
Wed Feb 23 00:02:33 PST 2005


on Tue, Feb 22, 2005 at 08:51:49AM -0800, Don Marti (dmarti@zgp.org) wrote:
> Virtualization was a big buzzword at LinuxWorld, and I'm starting to
> suspect it's a load of crap.

90% of everything is crud.

That counts for most of what I'm saying here, particularly as my
exposure is minimal.
 
> Why would you partition a big expensive server into the equivalent of
> several small cheap servers that add up to a fraction of the big
> server's price?

Depends on n.  For certain uses, fully partitioning out environments
leads to both configuration and security wins.

As others have pointed out:  sometimes hacking something to pieces is
valuable because you can glue it back together again.  If you can:

  - Virtualize a sysem (VM).
  - Yoke together virtualized systmes (virtual clusters, as mentioned),
    or
  - Dynamically extend VM's resources (disk, CPU, RAM, net).
    or
  - Dynamically shuttle VMs across the real machine, to different real
    machines, or to different real datacenters.  Redundancy is a big
    win.

...you've got an increased level of flexibility.  How much that's worth,
and to whom, I don't know.  What I *do* know is that flexibility (a
synonym for "choice" -- the one word which never appears in Microsoft's
"marketing collateral") is a major selling point for GNU/Linux.  Hell,
who'd want to put a TTY in a GUI?  But that's what the 35-odd rxvts are
on my desktop at the moment.

Another possible win:  backups suck.

Solution:  virtualize your system.  Clone system to another VM.  Back-up
the now-idled initial VM.  Full system image.  Hell, you can hot-start
from a given state, not just disk, but memory and running processes.


There's another related buzzword that's popping up again:  Utility
Computing.  Basically another spin on leased services.  Two articles in
Monday's SF Chron.  Smells like Sun, IMO:


    UTILITY COMPUTING
    Technology firms betting heavily on pay-per-use IT
    Benjamin Pimentel, Chronicle Staff Writer
    Monday, February 21, 2005
    http://sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2005/02/21/BUGM0BBHCR1.DTL&type=tech

    The supposed next big thing in technology is so new, there's
    disagreement on what to call it.

    Some call it grid computing; others prefer utility computing.

    Or as Sun Microsystems Inc. Chief Technology Officer Greg
    Papadopoulos said a few months ago, his boss, Chief Executive
    Officer Scott McNealy, calls it "the 'big friggin' WebTone switch."

    <...>

    For companies big and small, it means that instead of buying big
    expensive boxes and hiring a bunch of engineers and technicians to
    run them, they would simply use a plug on the wall to access all the
    IT power they need -- whether for processing payroll, dealing with
    customers or maintaining employee records.



    UTILITY COMPUTING
    Small firms can act like the big boys

    Benjamin Pimentel, Chronicle Staff Writer

    Monday, February 21, 2005

    As the owner of Teddy Bear Quilts, a small fabric shop with four
    employees in Santa Rosa, James Hahn can't afford to set up a fancy
    computer system to run his business.

    But that hasn't stopped him from gaining access to sophisticated
    technology through pay-per-use software services. For example, Hahn
    manages his payroll through Intuit's QuickBooks, an online service
    that costs him roughly $650 a year. 

    ...

    Analyst David Tapper of International Data Corp. said small
    businesses will be decisive in the growth of utility computing.

    "Ultimately, the litmus test ... for IT delivered more or less like
    a phone service or electricity will be whether average-sized firms,
    mom-and-pop shops and even consumers will eventually procure some or
    all of their IT capacity as a utility from a service provider," he
    wrote in a July paper. 


My read:  such systems lead to the inevitable problem:  your business
data sits on someone else's server, at their control, and subject to
denial of access on the basis of your ability to pay a monthly bill.
That to me is a high business risk.


ObChronDoesGood plug:  the SF Chron may be a half-rate paper.  But it's
got an excellent and comprehensive online archive dating to 1995.
Beujolais.


> And why would you license a fancy virtualization layer when you could
> just buy blade servers?

Blades:

  - Expensive on a per-CPU basis.

  - Proprietary form-factors and management.  Ask anyone who's invested
    in RLX kit (to name one struggling vendor).  I've seen the company's
    pitch, and it's a nice show.  But they're selling to a small market.

  - Heat, as previously mentioned, particularly at low utilization.

  - Flexibility, as previously mentioned.

A lot of shops that you'd think would run blades or server racks instead
run commodity hardware.  It's cheap.  It's still cheap when you factor
in amping up the room AC.  And advanced configuration management systems
often conflict with home-grown systems.  It's really hard to do system
management well....

 
> Real or virtual, you still need to manage the servers -- so why not
> just put in good management software (including power management,
> which you really need for big blade installations) and skip the
> virtualization malarkey?
>
> Who cares about the percentage of utilization of a resource that's
> really cheap?  

There's a few schools of thought on that.  In a class by itself is, of
course, Google.  But they apparently load their systems (at least to
their definition of load) and own both the box and its net benefit.
Incidentally:  what's the size of the Google farm these days, and do
they _really_ need n*10K systems?  I suspect a lot of reserve capacity.

In sufficient quantities, virtualization can offer savings.  The real
place for that though is large datacenters, and you're probably looking
at a handful of vendors.  IBM and, um, IBM.  EMC likely too with their
VMWare aquisition.

The real value-add is probably the same as in grid computing:  you've
tied up your customer assets in your virtualization scheme, and they
can't get out easily.  Beware lock-in.


> -- but, really, isn't the virtualization frenzy just a smokescreen to
> try to put some profits back into the generic server/generic OS
> market?

Yathink?!


Peace.

-- 
Karsten M. Self <kmself@ix.netcom.com>        http://kmself.home.netcom.com/
 What Part of "Gestalt" don't you understand?
    I'm only buying black equipment until they invent something darker.
    - LRPD
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