VMWare (or Virtual Machine Software) is exactly that, a software program that emulates an entire PC system, you may ask what purpose this serves, and why would anyone want to emulate a PC when a real one would perform much better? There are a number of answers to that, but first let me give you a hypothetical situation.
You are the systems administrator for a medium sized company, its coming up to year end and your budgets all but gone, you have been informed the company wishes to deploy several new server technologies to the network, including SMS 2003, ISA Server 2000, MOM and Live Communication Server, this is all daunting to you as you have never used some of these products, and feel it will all go horribly wrong, your company, being they just spent a fortune on software, its the end of the year, and there tight gits anyway, have refused your request for a Training budget.
- Testing -
Here comes the first strenght of VMWare, especially VMWare Workstation, in a matter of hours you could of configured on your very own desktop, four Windows 2000/2003 Servers, one running SMS, one running ISA, one running MOM and one running Live Communcations Server, all interacting together in the confined network space you have allocated to them, not only does this allow you to train, test configurations and combatibility of the above servers, it also allows you to monitor how these servers behave together in an environmnt, without needing four seperate servers to test on, you could also deploy a client machine in VMWare to test how they integrate with your existing clients and what problems this may cause without having to segregate your network/dedicate equipment to the task. This strength alone makes VMWare a top contender in an administrators must have software arsenal.
- Consolidation -
Migrating? need Backward compatibility? these are the selling points of VMWares GSX server line, GSX server is an enterprise level Virtual Machine software capable of running on dual and quad processor systems, this system is ideal for companies wishing to migrate, but wanting to leave some form of legacy systems in place, it also allows the powerful modern hardware behind Blade Servers to be utilised even more fully, by deploying VMWare GSX Server across an array of Blade servers you can fit a racks worth of smaller servers in a quarter of a rack! \nIn my experiance the GSX server is highly robust, and given the right hardware performs excellently, most of the time you wont even know your connecting to a 'virtual' machine, its a pretty costly system and I have not come across many places that use it, but those that do achieve some pretty neat things with it.
- Training -
Heres the important one \nsimilar to the testing trait, VMWares ability to assist training and certifcation candidates is unquestionable, you can establish a versatile LAB environment with minimal cost and effort, that can be changed around in a matter of hours (minutes if you know what your doing) and as the nature of training dictates you tend to work on one area at a time, you can construct very elaborate configurations without problem, whilst only working on the machines you need for the perticular task at hand. Machines can be fully customized from the default settings, with multiple NICs and Hard disks added, including directly utilising a physical disk or partition (for greater performance) VMWare also allows varied different styles of network access, allowing you to build a completely seperate environment to train in.
- Tips -
Suspend is your friend
Suspend mode in VMWare is great, it may sometimes take a while to suspend a machine, but not usually as long as it takes to reboot, and you can 'pause' whatever your doing on certain machines when you need the performance for other tasks
Power only what you need
VMWare will happily allow you to create 10s, 100s of Virtual machines (disk permitting) all forming a vast and elaborate network topology for your training needs, but rarely are all these items required at once, and VMWare would never actually let you run 100s VMs at the same time, so work out your tasks at hand, and what is required for it to work, testing domain trusts? just power up two domain controllers, testing RIS? the RIS Server, DC and Client should be sufficiant, use this with the suspend mode to instantly alter your 'active' LAB to meet current needs without having to run your machine at a snails pace
DNS DNS DNS
For all you Microsoft candidates out there, remember the importance of DNS, and remember to have one running at almost all times in your VM environment, this is done usually in the form of a DC, I personally only switch my DC off when im doing multiple client installs that dont require it, its required for almost all AD and Advanced windows features, so dont forget to power it up
Dont just leave VMWare to pick its memory allocation, give it an inch, and..
Well ok VMWare isn't that badly behaved, but it does usually take more memory than required, fine tune it to get the most out of your virtual lab
Rough Guidelines (other factors of your machine may effect this)
Windows Client - 128MB
Windows Server - 256MB
Linux Server - 128 - 256MB
Linux Client (X) - 256MB
Linux Client (SH) - 64 - 128MB
- System Considerations -
Whilst VMWare will run on most machines, in order to get the most out of it, you will need a client PC that can effectivly run 3 or 4 virtual machines together, 2 is sufficiant for most tasks, but as more advanced stuff comes along you will want to test with more than two devices at once, VMWares primary resources are RAM and HDD, a Virtual machine will hog memory, and use lots of disk space and disk swaps if you push your luck, here are some following hardware recommendations for a decent Virtual Lab
HDD 100GB 7200RPM (8mb cache preferred)
the rest is really down to you, I only use a Netgear FA311 in my setup and a Broadcom built in Gigabit port, both seem to work fine without problems, VMWare emulates an AMD PCNet 32 network card anyway, so remember this when installing linux and such things that require manual selection of the driver.
- Lab Considerations -
This i leave upto you, you can find various reports of lab configurations around the forum, that we have set up for various exams, for the current exam I am studying for (70-294 thanks to Trip) I have a VLAB set up as follows
3x W2k3 Servers (1 with 2 HDDs)
2x WXP Clients
1x W2k Client (RIS setup thanks to new VMWare 4.5 PXE Support)
I am also playing with ISA Server 2004 with the following set up
3 W2k3 Servers (1 with ISA 2004 and 3 NICs)
2 WXP Clients',