Server Differences?

[matrix0978]

Ive never understood, whats the difference between and Dedicated server, and a Virtual Server?

[Daemonforce]

I prefer descriptions between physical and virtual.

I use a physical server because I can depend on it not killing itself whenever I need to do a critical download.

On my workstation, a virtual server is ok for unimportant tasks(like making changes to the physical server), but if I'm in the middle of a game and this computer overheats and reboots, everything my virtual server was doing is gone. This is why I have and prefer a physical server over anything. Running a virtual server on a physical server would be absolutely perfect because if your installation has a critical problem, you can always run a snapshot and go back to when things worked. I can't do that on my physical server because the load would be a likely cause of intermittent reboots. =/

[matrix0978]

but what IS a virtual server?

[nmX.Memnoch]

Virtual Server 2005 Frequently Asked Questions

Q. What is virtual machine technology?

A. Virtual machine technology applies to both server and client hardware. Virtual machine technology enables multiple operating systems to run concurrently on a single machine. In particular, Microsoft Virtual PC products enable one or more operating systems to run on the same computer system as the current Windows operating system. Today, many x86-based operating systems are supported by Virtual PC 2004 and Virtual Server 2005. In addition, Virtual PC for Mac enables one or more other operating systems to run on the Macintosh operating system so that users can run a Windows operating system and Windows applications on a Macintosh.

Q. What is virtual machine technology used for?

A. Virtual machine technology serves a variety of purposes. It enables hardware consolidation, because multiple operating systems can run on one computer. Key applications for virtual machine technology include cross-platform integration as well as the following:

• Server consolidation. If several servers run applications that consume only a fraction of the available resources, virtual machine technology can be used to enable them to run side by side on a single server, even if they require different versions of the operating system or middleware.

• Consolidation for development and testing environments. Each virtual machine acts as a separate environment, which reduces risk and enables developers to quickly recreate different operating system configurations or compare versions of applications designed for different operating systems. In addition, a developer can test early development versions of an application in a virtual machine without fear of destabilizing the system for other users.

• Legacy application re-hosting. Legacy operating systems and applications can run on new hardware along with more recent operating systems and applications.

• Software demonstrations. With virtual machine technology, users can quickly recreate a clean operating system environment or system configuration.

• Simplify disaster and recovery. Virtual machine technology can be used as part of a disaster and recovery plan that requires application portability and flexibility across hardware platforms.

This, of course, applies only to the Microsoft Virtual PC/Server technology. Basically, a physical server can run any number of virtual servers, within it's resource (CPU/RAM/etc) limits. Intel, AMD, Microsoft, and others are trying to push it for everyday usage, but I think it still has a long way to go for that. Sure, the server hardware is definitely powerful enough to run multiple virtual servers in certain instances, but you're putting everything down to one point of failure. Admittedly though, a virtual server is much easier to recover since all you have to do is restore the virtual hard drive files on another physicaly server and you're back in business.

Peronally, I'm only confident enough in it at this point for testing and development environments. Give it another few years and it'll definitely be to a point where it can be used for live business applications.

[WBHoenig]

I don't think he means a VM.

In webhosting, a dedicated server is your own server, usually hosted and maintained by a webhost. A virtual dedicated server is shared hosting, BUT you are sharing with very few people (mabye 20 instead of 5000)

[XPerties]

All the above is incorrect.

Shared Hosting is many clients on one server sharing all resources. What one client does affects others.

VPS or virtual private server is splitting a single physical server into multiple virtual servers. Virtual private servers are sometimes called virtual dedicated servers. Each VPS would have it's own kernel, own firewall and certain resources would be assigned to each VPS. Example would be a 2Ghz CPU split into 2 VPS would give each client a 1Ghx usuage of the CPU and if the VPS had 2 gig of Ram then each client would get 1 gig. Many companies will place 5-10 clients on a dedicated server and split the resources at which time it is considered a VPS.

A dedicated server is you using everything the server has to offering.

[-I-]

All the above is incorrect.[/qoute

actualy all of the above is true....

Vertual machines even in webhosting are to be concidered dedicated OS's that run side by side (even though in a webhost apliance doesn't usualy run on a MS-vertual server instance, and usualy doesn't run in win32 os's.

but you're putting everything down to one point of failure. Admittedly though, a virtual server is much easier to recover since all you have to do is restore the virtual hard drive files on another physicaly server and you're back in business.

thats why most it-profesionals dont run a vertual machine on a single server but rather on a cluster of servers.

lets say you have 4 critical tasks,

(example:

> a database server,

> a mail server,

> a domain controler (or user-management server),

> and an aplication server

You'd probably at least nead 3 fysical servers. or more (depend on load)

but even if you wanted 4 machines virtualization still could be something for you

because, what if one of your fysical machines fails?

? do you want to lose your mailserver or how about having your database ofline for an hour (at least).

if it was hosted as a vm cluster the other physical machines would just take over, and your access might become slow, but not not unavail...

Pro, if 1 physical machine fails. it may be a botle neck but all your systems will stay online ...

Con, running vm software takes resources, so you may nead the extra powerfull (thus more expencive) hardware.

con, VMsoftware is expencive to aply, even though there are opensoure variants... you still nead to pay the guy who will set it up for you..

Edited April 21, 2006 by -I-