hardware and software vendors are rapidly embracing virtualization.
However, database vendors have been a bit slow to the dance. It
could be that database vendors and DBAs believe that database tuning
requires direct access and control over low level IO subsystems for
optimal performance. But if the hardware is say, ten times faster,
what does a 10-20% overhead for virtualization matter?
Although Oracle's MOSC has some documents which state that
Oracle has not yet verified or certified the database for virtual
machines, it has been the author's experience that virtualization
abstraction does not impede nor complicate database deployment,
management or tuning. In fact, it seems to simplify it. The only
area that poses some additional questions/issues is backup and
recovery. B&R has been complicated far earlier by cheap hardware and
hardware technologies such as RAID.
The real proof for support lies with the CPU vendors - both Intel
and AMD have introduced
virtualization support in their newer chip designs. With faster
clock speeds and ever growing multi-core chips, resource utilization
has become key and most CPUs sit idle much of the time. Thus, server
consolidation makes total sense; also, the space and power savings
gain result in leaner and greener computing centers. And with the
proliferation of computing systems, these savings can be quite
substantial. One recent article stated that the power savings alone
in one company's experience paid for the entire cost of the reduced
space needed. This clearly shows that secondary costs such as these
are becoming more mission critical than hardware performance and
direct costs. In fact, a 100-year old university told me that they
could not upgrade their electrical systems in older buildings for
their increasing computing needs. Therefore, power requirements
alone were the new primary limiting factor in all future hardware
Given the clear benefits and these leaner and greener trends, I
would not bet against virtualization going forward. It's not a
luxury but, quite often, a necessity these days. And this will only
increase with time.
Why VMware Server?
So why did this book choose VMware Server? The
answer is simple: it's free, works flawlessly, is compatible with
their non-free products, and VMware has something like a 70% market
share. All that means it is a perfect basis for a book. Not only can
you download it for free and use this book's virtual appliance
contained on the included DVD, but it's quite likely that your
current or future virtualization needs will include some VMware
That's not to say that other vendors? products
are inferior in any way. In fact, since the other products like
Microsoft Virtual PC and Virtual Iron are also free, they are also
great candidates. However, VMware's popularity, hands down, makes
the book universally more applicable. Note that most concepts or
techniques mentioned within this book are similarly universal in
nature. This means that they should apply, with minimal changes, to
these other virtualization platforms as well.
I don't have a magic crystal ball or I would
have made a few million in the market and retired already. But it
seems clear that the trend is for increased virtualization at nearly
Back in the mid-1960's and early 1970's,
mainframes had sufficient excess CPU capacity that warranted the
creation of virtual machines (e.g. IBM's VM - which was the origin
of the term hypervisor). Contemporary multi-core CPUs and cheap
memory make even today's hungriest applications seem tame. So once
again, we have spare or excess hardware capacity - even on lowly
notebooks and laptops. It seems that there is as much a need for
virtualization today as 40 years ago!
Also, today's database administrators and
application developers need to work within ever complex and changing
environments. Yet again, virtualization is the easiest way to
conquer these challenges. Look for virtualization to become prolific
and mainstream technology.
Oracle's Own VM
At Oracle Open World 2007, Oracle shocked quite
a few people by announcing their own new virtual machine offering:
Oracle VM. Oracle claims that it is up to three times faster than
other server virtualization product. Now with their Enterprise
Linux, Oracle VM, Oracle database, Automatic Storage Management (ASM),
the Oracle Cluster File System (OCFS), Oracle has truly become a
robust and comprehensive vendor for database infrastructure.
Moreover, with their recent applications space acquisitions, Oracle
has become a genuine ?one-stop-shop? for running large, scalable
This book was already half written when Oracle
VM debuted and besides, I really do like VMware. Referring again
back to Figure 1, Oracle VM is nothing more than repackaging of the
open-source based Xen offering (recently acquired by Citrix). It is
just another hyper-visor or para-virtualization solution whose core
is based upon a streamlined version of Linux (which is the exact
topic of Chapter 3). The Oracle VM User Guide displays its
architecture with Figure 4 shown on the next page.
This is an excerpt from
Oracle on VMWare:
Expert tips for database virtualization
by Rampant TechPress.