21. What
products are available for Server Virtualization?
Bare
Metal Hypervisor / Native / Type 1: VMware ESX Server
Microsoft
Hyper-V Citrix/Xen Server
Hosted
in an OS /
Type2: VMware Server
Type2: VMware Server
Microsoft
Virtual Server Parallels Server
22. What
products are available for desktop virtualization?
Host
in an OS / Type 2 / intended for workstations: VMware Workstation
Microsoft
Virtual PC Parallels Workstation VMware Fusion for Mac OS Parallels Desktop for
Mac OS
23. What
is the difference between ESX Server and VMware Server?
While
both ESX Server and VMware Server are server virtualization products, the
difference is that VMware ESX installs and runs on the bare metal of a physical
server where as VMware Server needs a base operating system. In other words,
VMware ESX has a type 1 hypervisor where as VMware Server has a type 2
hypervisor.
You
will obtain must better performance from ESX Server as it has much less
overhead. ESX Server also has many features available such as VMFS, VMotion,
VMHA, and DRS. On the other hand, ESX Server is also a commercial product that
must be purchased where as VMware Server is a free product. VMware Server is an
excellent option to choose to slowly migrate to server consolidation at a low
cost. VMware Server is also an excellent way to learn about virtualization as
well as a way to run multiple operating systems on your desktop PC, at no cost.
24.
What is the difference between Hyper-V and Virtual Server?
Like
the difference between ESX Server and VMware Server, Hyper-V and Virtual server
have similar differences. Hyper-V is a type-1 hypervisor where Virtual Server
is a type 2 hypervisor. Virtual Server requires that you first host a Windows
operating system to load it.
Hyper-V
is meant to be a higher performance commercial virtualization platform with a
centralized management platform and 3rd
party add-ons. Virtual Server, on the other hand, is a free virtualization
platform meant for the desktop or for small-scale server virtualization
solutions.
25.
What is the difference between emulation, native virtualization, and
paravirtualization?
Emulation
is where software is used to simulate hardware for a guest operating system to
run in. This has been used in the past but is difficult to do and offers low
performance.
Native
virtualization (or full virtualization) is where a type-2 hypervisor is used to
partially allow access to the hardware and partially to simulate hardware in
order to allow you to load a full operating system. This is used by emulation
packages like VMware Server, Workstation, Virtual PC, and Virtual Server.
Paravirtualization
is where the guest operating systems run on the hypervisor, allowing for higher
performance and efficiency. For more technical information and videos on this
topic, visit VMware’s Technology Preview for Transparent Virtualization.
Examples of paravirtualization are Microsoft Hyper-V and VMware ESX Server.
26.What
are the different types of virtualization?
Server
Virtualization – consolidating multiple physical servers
into virtual servers that run on a single physical server.
Application
Virtualization – an application runs on another host from
where it is installed in a variety of ways. It could be done by
application streaming, desktop virtualization or VDI, or a VM package (like
VMware ACE creates with a player). Microsoft Softgrid is an example of
Application virtualization.
Presentation
Virtualization – This is what Citrix Met frame (and the ICA
protocol) as well as Microsoft Terminal Services (and RDP) are able to
create. With presentation virtualization, an application actually runs on
another host and all that you see on the client is the screen from where it is
run.
Network
Virtualization – with network virtualization, the network is
“carved up” and can be used for multiple purposes such as running a
protocol analyzer inside an Ethernet switch. Components of a virtual network
could include NICs, switches, VLANs, network storage devices, virtual network
containers, and network media.
Storage
Virtualization – with storage virtualization, the disk/data
storage for your data is consolidated to and managed by a virtual
storage system. The servers connected to the storage system aren’t aware of
where the data really is. Storage virtualization is sometimes described as
“abstracting the logical storage from the physical storage.
27.
Why do I care that VMware ESX uses the VMFS?
VMware’s
VMFS was created just for VMware virtualization. VMFS is a high performance
cluster file system allowing multiple systems to access the file system at the
same time. VMFS is what gives you the necessary foundation to perform VMotion
and VMHA. With VMFS you can dynamically increase a volume, support distributed
journaling, and the addition of a virtual disk on the fly.
28.
How do I backup my virtual guest operating systems?
There
are multiple ways to backup your virtual guest operating systems. As long as
your critical data is sent offsite and follows your backup rotation, you are
doing well.
One
option would be to run a a backup client inside each guest operating system,
just like you do your physical servers.
If
you are using a bare metal virtualization platform (like ESX Server), the
greatest challenge is sometimes gaining access to your data. For example, with
ESX Server, your data is stored inside ESX Server’s VMFS file system. That file
system cannot be accessed by a typical Windows or Linux backup client. For that
reason, there are specialized virtualization backup products like Vizioncore’s
vRanger an EsXpress.
29.
What are VMware VMotion & Storage VMotion (SVMotion)?
With
VMotion, VM guests are able to move from one ESX Server to another with no
downtime for the users. What is required is a shared SAN storage system between
the ESX Servers and a VMotion license.
Storage
VMotion (or SVMotion) is similar to VMotion in the sense that it moves VM
guests without any downtime. However, what SVMotion also offers is the
capability to move the storage for that guest at the same time that it moves
the guest. Thus, you could move a VM guest from one ESX server’s local storage
to another ESX server’s local storage with no downtime for the end users of
that VM guest.
30.What
is VMware HA?
One
of the most amazing capabilities of VMware ESX is VMHA. With 2 ESX Servers, a
SAN for shared storage, Virtual Center, and a VMHA license, if a single ESX
Server fails, the virtual guests on that server will move over to the other
server and restart, within seconds. This feature works regardless of the
operating system used or if the applications support it.
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