Network Tips
What is a Virtual Machine and How Do I Chose One?
Why use a Virtual Machine(VM)?
Let’s start with the basics. What is a Virtual Machine (VM)? Well put simply a Virtual machine is a Operating System (like windows XP, Windows 7, or a Linux OS) that runs on top of another Operating System, but that you can use and interact with as though it is it’s completely own system. For example Windows 7 has an optional feature of a Windows XP Virtual Machine. In this case the computer is primarily running Windows 7, but there is a desktop emulation running much like any other program (say Word or Excel) that is the entire Windows XP environment allowing users to log into it and run ALL of the Windows XP programs that are installed on that virtual desktop.
Why use a Virtual Machine?
There are many reasons one might use a virtual machine environment. I’ll start by telling you that we at Longwell Technologies have been using Virtual Machines since about 2001 and have found the EXTREMELY useful for development, support and testing environments. Here are several things that companies use VMs for:
- Setup a Testing or Development Environment- One great use of a VM environment is to set up a quick, inexpensive and disposable testing or development environment for creating and testing new applications with full network, internet, database, custom file structures, etc. without the added expense of hardware or the expense of additional physical storage space needed for additional hardware.
- Try out a new operating systems- Want to try out a new Linux OS? Put together a VM and build it on it. Suddenly, you can launch and try dozens of operating systems without much hassle.
- Testing new software- You can use VMs to try your software or web app or even site design on a variety of boxes by just building VMs and running the tests there. Because the “machines” boil down to a couple of files, therefore, you can quickly and easily copy them and or back them up. You can burn the VM image onto a CD or DVD and ship a fully configured system to anyone anywhere.
- Backup your system- When you get ready to move from XP to Vista, you can use a VM to make a backup of your old system. If things go horribly sour, you could have the VM version up and running in short order. By the way, you can have TWO servers, and have a copy of the VM on both. This would give you even more business continuity, should something happen to the server.
- Save Legacy Systems- Offices and data centers often have an old box around that just can’t be mucked with. There’s additional software you can use to do what’s called a P2V switch, a physical-to-virtual conversion, where the old box’s “image” gets copied onto the virtual machine files, and thus, gives you a hopefully-operational clone of the old grandpa box in the corner.
How to Chose VM Software?
The two most popular virtualization products are VMware and Microsoft’s Virtual PC/Server. So how do you choose the right product for your needs?
Understand Your Needs
No matter what your needs, it is very likely that one of these products will be able to do the job. The key to choosing the right product is understanding your overall needs. What is it that you want to do with virtualization? Do you want to have a test network on your desktop PC? Do you want to do software development? What features are needed? How many servers will you run concurrently? How much RAM is required? What operating systems will be run in the virtual systems? The answers to these questions will help you choose the right class of virtualization product.
Choosing the Class of Virtualization Product
Once you take a look at your needs, you will be able to better choose the class of virtualization product you need. For example, if you just want to run a test Windows 2008 server and Windows 7 workstation, on their own private network, on your local desktop PC, then you should choose a desktop virtualization product. Examples of these are VMware Workstation and MS Virtual PC. Both of those applications are designed to be run on a local desktop.
On the other hand, if you need to run 5 concurrent production servers that required at least 1GB of RAM each, you are no longer talking about a desktop product. You require an enterprise virtualization server product. Not only because of the amount of RAM required but because we said that we would run “production servers”. You don’t want to run production servers on desktop virtualization products.
Choosing Between VMware and Virtual PC
Let’s say that you want to setup a basic server & workstation isolated network and run it on your local desktop PC. You know that you can choose between VMware workstation and MS Virtual PC. So how do you make that choice? Let’s compare these two competing applications. Below, I will list out pro’s and con’s of each of these applications. As always, with pros and cons, some of them can be debated.
VMware Workstation 7
Pros
- VMware came out with their virtualization product in 1999, 4+ years before Microsoft. Because of this, VMware is a mature product. Microsoft actually bought their product (called Connectix) and made it run on Intel systems.
- VMware is more “feature rich”, in general.
- VMware’s virtualization product line has more depth that Microsoft’s. VMware offers products like ACE, VirtualCenter, and ESX server.
- While both support Linux with Linux Tools/Additions, support for Linux distributions in VMware is stronger. Also, VMware offers help information for over 50 different OS distributions.
- VMWare can be run on Linux as its main OS was well as a Virtual OS.
- Performance benchmarks for VMware, when running Windows XP, give it higher marks than Virtual PC. In my experience, VMware workstation does perform better.
- Snapshot manager offers ability to freeze systems in time, keep track of these different system images, and move forward and back between them. You can even branch off system snapshots and create new snapshots.
- VMware Team features allow you to group virtual systems together and start/stop them all at the same time.
- Ability to import Virtual PC machine.
- Ability to create AVI videos of tasks performed inside virtual machines
- Support for 64 bit Guest Operating systems if you have a 64 bit processor
- Supports dual processors on virtual machines
- Supports USB devices
Cons
- VMware Workstation costs $189 whereas Virtual PC is free
MS Virtual PC (2004 SP1)
Pros
- Much lower cost – Virtual PC 2007 is free whereas VMware Workstation costs $189 if you download it.
- Simple and easy to use – limited interface and features
- Can transport virtual machines from Virtual PC to Virtual Server
- Support Sound on virtual machines.
Cons
- Less documentation is available for Virtual PC.
- Overly streamlined design hides additional features or more complex configuration.
- Performance benchmarks for Virtual PC, when running Windows XP, give it lower marks than VMware.
- Questionable Support of some Linux environments.
- Virtual PC can only be run on Windows OS as the primary OS.
- No USB support beyond keyboards and mice.
- Many other advanced features offered by VMware Workstation are missing (like snapshot manager)
Both VMware and Microsoft offer their server products for FREE. However, using the server class products on your desktop system may not be the best choice. The server class products are designed to run production servers. Workstation class products have more user-friendly features, with the desktop user in mind. This goes back to knowing your requirements.
In the end, I’m not going to tell you which product to use. From the list of pros and cons above, you should be able to make that choice for yourself. In my opinion, either choice is a good choice. Both products are popular because they are good products. If, after considering the pros and cons above, you still have trouble choosing the right desktop virtualization product, I highly recommend that you do a demo/evaluation of each of the products. That way, you can see the products for yourself. To try out VMWare Workstation 5 go to the VMware workstation 30 day evaluation download page. To download Microsoft Virtual PC, go to the Virtual PC homepage at Microsoft.com. I can tell you that, if you will use the extra features offered by VMware Workstation, they are definitely worth the cost difference between the products.
Summary
In summary, prior to choosing a virtualization product, you should first consider your needs. Ask yourself what you will be using the product for. Once you understand your needs, you can move on to choosing between vendors. Best of all, you don’t have to make that choice just from this list, you can try out the products yourself. One thing that I am sure of, once you begin using virtualization you will wonder how you ever did without it.
Here at Longwell Technologies, we use both. There are cases for using MS Virtual PC for our testing and developing environments that make it very easy for us to work with, where in other cases we find that VMWare is the better solution for Linux environments that can help us support some of our Linux customers better.
Bluetooth vs. Wireless USB
Since 1999 when bluetooth was first introduced, you have probably used bluetooth for wireless keyboards, mice, headset, GPS and other peripherals cellular phones, PDAs, MP3 players, and some digital cameras. If so, you know how convenient the wireless connectivity can be. You’ve probably also connected many of those same devices up using a wired connection called USB. There is a new wireless standard that is growing called Wireless USB.
What Cloud Computing is and how it relates to a Cloud Service.
There is a lot of talk around about Cloud Computing, but very little talk about what Cloud Computing is. I know I’ve heard people talk about it as all kinds of things, some like a cloud service are right and some like grid computing are wrong.
The term “Cloud” has been used to generically define the internet for many years now. For example, “… then we will deliver the information out to the cloud where it will then be picked up by the subscribers.” But when we add the word “Computing” things at first seem to become more specific, but quickly it becomes apparent that this can be an even fuzzier term. So though cloud computing is a rather broad concept, there are definitely some thing that cloud computing is, and some things it is not.
Why Cloud Computing?
Cloud computing has come about as a response to companies needing to increase their IT capacity and capabilities quickly, easily and without having to make huge investments in hardware, staff, and training. This is fantastic for small to medium sized businesses who are looking to outsource most of their IT needs. It can also be great for large companies who are reaching the peak of their resources to increase their capacity without having to build new or larger data centers.
Cloud Computing is not Grid Computing
One thing Cloud Computing is not is it is not the same as Grid Computing. Grid computing is primarily for heavy computational needs. In order to evaluate information from say a large data pool that requires a large amount of processing time the information can be split out to many different computers running the application and they separately process the information and send it back to a main coordinating set of computers to either store, or redistribute the results for further processing. One of the largest examples of this is the Seti@home Grid Computing project by Berkeley University that analyzes radio telescope data that sends data to personal computers around the world for scanning to look for signs of intelligent life outside of Earth.
Examples of Cloud Services
Cloud computing is more focused on services called a cloud service. These cloud services are subscription or pay per use services offered in real time over the internet extending an IT’s capacity and capabilities. Here are a few common types of cloud services
1- SaaS (Software as a Service) is an application run through a browser for many customers to use. For the customer this means they have easy access to the application at a reasonable monthly/annual charge for use saving them on their upfront investment costs for servers, software licensing, and IT support. Web Field Service Trakker is an example of this type of application. Allowing an immediate low cost SaaS cloud service application for dispatching, scheduling, CRM, inventory control and invoicing.
2- Utility Computing is usually used for non-mission-critical needs such as data storage. One obvious example would be using such a cloud service to remotely backup company data to.
3- Web Services are services available to application developers to enable them to create applications that will contact over the internet to a web server and request information such as the services offered by FastTrakker where the FastTrakker web service can return information about who visited your website and what pages they looked at as well as tracking outgoing emails to see if they were read and emails were clicked on.
Hopefully this helps you start to get an understanding of what Cloud Computing is and what a Cloud Service is, so that the next time you are in a meeting and it comes up you will know if the person presenting actually knows what they are talking about and you can participate, or if they are just incorrectly using a buzz word.
Difference between Hub and Switch and Router
What’s the difference between a Hub, a Switch and a Router?
Very simply it could be said to be “Intellegence.”
It has come to my attention that these are very easily confused by many people. When you walk into a BestBuy or other electronic store and look at the network connectivity aisle you’ll find many different hubs, switched and routers.
So which one do you want? What is the difference between a Hub, a Switch and a Router?
Well let’s start with looking at what’s similar about them and why they are all in that same aisle. Hubs, switches, and routers are all devices that let you connect one or more computers to other computers, networked devices, or to other networks. Each one has ports to plug cables to connect multiple computer or video game systems. In addition many offer a wireless WiFi to connect even more devices to without cabling.
So that’s how they are similar now, what is the difference between a Hub, a Switch and a Router?
A Hub
a hub is typically the least expensive, least intelligent, and least complicated of the three. Its job is very simple: anything that comes in one port is sent out to all of the others. That’s it. Every computer connected to the hub “sees” everything that every other computer on the hub sees. The hub itself does not know anything about the data being transmitted.
A Switch
A switch does essentially what a hub does but more efficiently. By paying attention to the traffic that comes across it, it can “learn” where particular addresses are. For example, if it sees traffic from machine A coming in on port 2, it now knows that machine A is connected to that port and that traffic to machine A needs to only be sent to that port and not any of the others. The net result of using a switch over a hub is that most of the network traffic only goes where it needs to rather than to every port. On busy networks this can make the network significantly faster.
A Router
A router is the smartest and most complicated of the bunch. Routers come in all shapes and sizes from the small four-port broadband routers that are very popular right now to the large industrial strength devices that drive the internet itself. A simple way to think of a router is as a computer that can be programmed to understand, possibly manipulate, and route the data its being asked to handle. For example, broadband routers include the ability to “hide” computers behind a type of firewall which involves slightly modifying the packets of network traffic as they traverse the device. All routers include some kind of user interface for configuring how the router will treat traffic. The really large routers include the equivalent of a full-blown programming language to describe how they should operate as well as the ability to communicate with other routers to describe or determine the best way to get network traffic from point A to point B.
So which do I want?
Depending upon what you are looking to do you probably want either a Router or a Switch.
If you need a piece of hardware to connect your computers to each other as well as to the internet you want a router. The router will usually have the capability to assign unique IP Addresses to all of the computers in your network and connect and share an internet connection.
If you already have a connection to the internet and IP addresses are already being assigned by a device (like the router or a server) but you need to connect more computers to your network, you most likely want a switch. You could use a hub but switches have been coming done drastically in pricing over the past several years and as stated above they are much more efficient. So I would highly recommend them over a simple hub.
I hope this helps give a basic understanding of some of the major differences between a hub, switch, and a router.
Automatic SQL server 2005 backup (Express)
I was looking to do an automatic SQL Server 2005 backup using SQL Server Express. SQL Server Express 2005 does not offer a built in way to backup automatically. So after doing a fair amount of testing and searching I finally figured out how it could be set up. The solution I use first of makes a local backup copy of the database. After that I use my normal backup software to save it onto a tape or other external device for offsite storage. (Note: I recommend to all my customers that they backup their data nightly onto rotating backup ‘tapes’ one for at least each day of the week, and then at least once a month take one of those to an offsite location).
Setting up an automatic backup, Step by Step
So first off, to make the local backup of the database you will need to have SQL 2005 Express Management Studio Express installed. Assuming you have that installed go ahead and start it and connect to your SQL 2005 Server database.
Next you will need to set up an SQL Server 2005 Backup Device.
- Click the + next to the Server Objects and you should see Backup Device.
- Right Click and select New Backup Device.
- Type in a Device Name (it can be anything you want but make a note of it for later reference)
- Select the radio box for File and browse for a location to make a backup copy of the database to.
- Click OK
That’s it for that part. Repeat this for all the databases you wish to backup.
Next we need to schedule a time for that backup to run. For this we can use the Windows Scheduler.
- Start the Windows Scheduler found in Start-> All Programs-> Accessories-> System Tools-> Scheduled Tasks.
- Double Click Add Scheduled Task
- Click Next
- Select any program from the list. I usually chose the calculator. It doesn’t matter because we are going to override this in a minute anyway.
- Click Next
- Name the task. I usually name it something like NightlyDBBackup
- Select Weekly if you are going to backup M-F. Chose Daily if you are going to backup every night including weekend.s
- Set the Time you want it to run. Remember this will briefly stop the SQL Server from running to run it at a time of day when it will be the least impactful.
- If you selected Weekly check off the nights you want it to backup.
- Click Next
- Fill in the Username and password for the user who has proper security rights to stop SQL Server, and has security access to the folder the database is to be backed up to. (Administrator almost always does)
- Click Next
- Check the Open Advanced Properties button
- Click Next
- This will open the task where we can now change the program from the calculator to the backup process.
- In the Run box delete whatever was there and replace it with the following
- sqlcmd -S localhost\SQLExpress -E -Q “BACKUP DATABASE MyDatabase TO MyDataSQLBackup WITH INIT”
NOTES:
- use localhost if SQL 2005 Server database is on the local computer, otherwise use the name of the machine is it on.
- use SQLExpress if that is the name of the DB part of the servername. (Both the localhost\SQLExpress name can be checked when you start SQL Express Management Studio Express because it asks upon startup each time what database you want to connect to)
- Change MyDatabase to the name of the actual database you wish to backup
- Change MyDataSQLBackup to the name of the Backup Device you created in step 3.
- use WITH INIT to so that the backup is not Appended. If you would prefer to Append to the backup each night (I do not recommend that, you will quickly start filling your hard drive and backup device) leave out the WITH INIT.
Test it and now your ready to go. You now have an automatic SQL Server 2005 backup process. Just set your backup software to backup your data at some point after this event is scheduled. I usually allow about 15 minutes, though in reality the DB backup usually runs in under 2 minutes.
