1. Server Virtualization
Elaborated by:
Maroua AISSA
Youssef HACHANI
Academic year : 2012/2013

2. Outline Introduction Conclusion & Performances
Virtualization
Server Virtualization
Server Virtualization’s Use domain
Server Virtualization’s Types
Server Virtualization’s Benefits
& Performances
VI. Server Virtualization’s Limitations
Conclusion

3. Introduction
Virtualization is a big opportunity presented today to solve a very big amount of problems.
Virtualization is now all the rage.
All servers in nearing end of life are now replaced by a virtual one.

4. Virtualization (1/2)
Virtualization is the creation of a virtual version of
something, such as an operating system, a server, a storage device or network resources.
‘Virtualized’ system
It makes it possible to run multiple Virtual Containers on a single
physical platform
‘Nonvirtualized’ system
A single OS controls all hardware platform resources

5. Virtualization (2/2) Why virtualizes? More efficient HW utilization
Long-term matching resources & needs
Quick and light server provisioning
Testing & Troubleshooting
More effective redundancy
HW maintenance w/o app downtime
Disaster Recovery (snapshot)

6. Server Virtualization (1/2)
Server virtualization enables you to run multiple virtual
machines simultaneously on a single physical server.
Anything you can do with a physical machine
you can do with a virtual machine.
The only difference is that you can’t touch it.
Many computers operate at only 10-15% of
their total computing capacity, leaving IT resources
untapped and unusable; with server virtualization
you can increase utilization to as much as 85%.
That’s intelligent usage of IT recourses!

7. Server Virtualization (2/2)
Server virtualization is the masking of server
resources, including the number and identity of
individual physical servers, processors, and
operating systems, from server users.
The server administrator uses a
software application to divide one
physical server into multiple isolated
virtual environments.
The virtual environments are sometimes called
virtual private servers, but they are also known as guests, instances, containers or emulations.

8. Server Virtualization’s Use domain
These following might be good choices for
virtualization:
Web servers ,File servers , Database servers ,
servers , Applications servers

9. Server Virtualization’s Types (1/9)
There are three methods to virtualize the server:
Full virtualization (Hardware Emulation)
Para-virtualization
Operating System (OS) virtualization.
While all the three modes have one physical
server acting as host and the virtual servers as
guests, each of the methods allocates server
resources differently to the virtual space.

10. Server Virtualization’s Types (2/9)
Full virtualization
Full virtualization uses a special kind of software
called an hypervisor.
The hypervisor interacts directly with the physical
server's CPU and disk space.
It serves as a platform for the virtual servers' OSs.
The hypervisor keeps each virtual server completely
independent and unaware of the other virtual servers
running on the physical machine.
Each guest server runs on its own OS .

11. Server Virtualization’s Types (3/9)
Full virtualization architecture:
Full virtualization

12. Server Virtualization’s Types (4/9)
Full virtualization drawback :
The drawback with this approach is that we are
adding another heavy layer of software between
the operating system and the hardware, so we
will notice slower performance.
But if we are consolidating various under-used
servers to save space and energy, this should not
be so much of a concern.

13. Server Virtualization’s Types (5/9)
2. Para-virtualization
The para-virtualization approach is a little different.
Unlike the full virtualization technique, the guest
servers in a para-virtualization system are aware of one
another.
A para-virtualization hypervisor doesn't need as much
processing power to manage the guest OSs, because
each OS is already aware of the demands the other Oss
are placing on the physical server.
The entire system works together as a cohesive unit.

14. Server Virtualization’s Types (6/9)
Para-virtualization architecture:
Para-virtualization

15. Server Virtualization’s Types (7/9)
3 . Operating System (OS) virtualization
An OS-level virtualization approach doesn't use an
hypervisor at all.
Instead, the virtualization capability is part of the
host OS, which performs all the functions of a fully
virtualized hypervisor.
The biggest limitation of this approach is that all the
guest servers must run the same OS.
Because all the guest operating systems must be the
same, this is called a homogeneous environment.

16. Server Virtualization’s Types (8/9)
Os-virtualization architecture:
OS virtualization

17. Server Virtualization’s Types (9/9)
Which method is best?
That largely depends on the network administrator's needs.
If the administrator's physical servers all run on the same
OS, then an OS-level approach might work best. OS-level
systems tend to be faster and more efficient.
If the administrator is running servers on several different
OSs, para-virtualization might be a better choice.
One potential drawback for para-virtualization systems is
support , the technique is relatively new and only a few
companies offer para-virtualization software. More companies
support full virtualization.

18. Server Virtualization’s Benefits & Performances (1/3)
There are many reasons companies and organizations are
investing in server virtualization :
Reduce hardware cost by up to 50% (by reducing the number of servers)
Reduce operational cost by up to 70% (energy bills, space leasing )
Use less power, generate less heat, take up less space, and consume fewer resources.
Deploy machines much faster by imaging instead of
building from scratch .

19. Server Virtualization’s Benefits & Performances (2/3)
Eliminate downtime due to hardware maintenance.
Insure flexibility : we can move data from that virtual
machine to another, without having to shut anything
down.
Provides load balancing by distributing the load
dynamically to other servers, With load balancers,
managing this change is automatic.
Provides higher availability independent of hardware,
operating system, and applications by ensuring
continuous availability against server failures.

20. Server Virtualization’s Benefits & Performances (3/3)
Establish Isolation : Each virtual machine is isolated
from other virtual machines on the same server to avoid
problems.
Implements migration
provides the ability to move
live applications automatically
from one physical server
to another with no
interruption in service.

21. Server Virtualization’s Limitations
For servers dedicated to applications with high demands
on processing power, virtualization isn't a good choice.
Too many virtual servers could impact the server's ability
to store data.
It's only possible to migrate a virtual server from one
physical machine to another if both physical machines use
the same manufacturer's processor.

22. Conclusion
As server virtualization technology advances, the need for huge data centers could decline. Here we can see the obvious need of network storage which also a related term in resource optimization of IT infrastructure and talking about these technologies lead us to cloud computing. It's not an exaggeration but virtual servers could lead to a complete revolution in the computing industry.

23. Thank You