Good article.
One thing I would add, being about 6 months after our first wave of server virtualisation, is that you soon start to think of other jobs that new virtual servers could do for you, and so does everyone else! If you are not careful, suddenly everyone in the organisation 'wants a virtual server to do XXX' and you no longer have the excuse that they are all busy or overloaded because they rightly point out that you can create a new server very easily.
Having got this far in our process, I would advise anyone starting this to plan for a large injection of virtual disk space, and maybe another host server or two about 6-12 months in. Then you can carry on providing as the demand picks up.
Hope this is helpful.
Simon
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Yes, that is correct, with a new SAN and Server Environment everyone and their brother in law wants to do something with the space or wants their VM's.
Physical servers are a single point of failure, unless you have a bare-metal rebuild in place to do it quickly.
Visualizing servers is the best thing to do in order to have HA, but you need to invest in VMware with licensing to allow you to lose a host and move on with life.
You can go cheap, but it will cost you more in the end.
Physical servers are a single point of failure, unless you have a bare-metal rebuild in place to do it quickly.
Visualizing servers is the best thing to do in order to have HA, but you need to invest in VMware with licensing to allow you to lose a host and move on with life.
You can go cheap, but it will cost you more in the end.
Good article.
A comment, under point#3 above regarding enterprise application making use of dongles for copy protection -
Dongle works pretty well in virtualized environment. The virtual machines are supporting USB devices plugged to physical machines and so does the USB dongles.
Same USB device can not be accessed from different virtual machines simultaneously and so does the USB dongle (which is good from copy protection standpoint).
A comment, under point#3 above regarding enterprise application making use of dongles for copy protection -
Dongle works pretty well in virtualized environment. The virtual machines are supporting USB devices plugged to physical machines and so does the USB dongles.
Same USB device can not be accessed from different virtual machines simultaneously and so does the USB dongle (which is good from copy protection standpoint).
We use a USB over ethernet device for virtualized servers that require a USB dongle to control software licenses. We also use a RS232 over ethernet with works just as well for serial devices.
In point #1 you mention the single point of failure. I just wanted to add Don't forget the san. If you choose to virtualize using High Availiblilty or Motion capabilities, you will require a single point of storage. I find it interesting that some of the best reasons to go virtual is to reduce single points of failure, yet we do so by using common storage devices. I understand that you can purchase 2 sans and implement some replication between the 2 and even have those auto failover with some vendors. some even support off site replication over wan links. I am just mentioning to be awar of this and to plan accordingly. Like one person mentioned. Go cheap in the beginning, pay for it in the end.
I agree, a SANS and the HOST can be failure points of an entire virtualized environement. I do think the cost savings from hardware and electricity use outway the costs and an ROI can be expected within a few years depending on your build. It is vital that failovers are put in place. It is also important that SQL servers or databases be tested in a sandbox before you try and move them over as these database servers usually are not the best candidates for virtualization. It would have been cool for companies if we didn't have to license everything, I know software companies need to make money and it isn't fair to them, but it would have saved a ton of more money.
I'm surprised there is no mention of backup plans. It seems to me there is a big hole in this technology with backing up VMs. There are the standard backup methods that can be used within the VM, but to take full advantage of the technology you need to copy that entire VM.
If you are not able to bring the server down to copy the VM for business reasons (24x7) there is software for live backups, but it is expensive and flaky from my understanding.
If you are not able to bring the server down to copy the VM for business reasons (24x7) there is software for live backups, but it is expensive and flaky from my understanding.
There are some difficult backup solutions out there but there are some good and relatively cheap ones as well.
SAN Snapshot aware solutions would be a first choice if possible.
vRanger is a good alternative for backups and is not complicated or expensive.
SAN Snapshot aware solutions would be a first choice if possible.
vRanger is a good alternative for backups and is not complicated or expensive.
Thanks for the info.
For someone without any VM experience, what are some good resources to get started with the basics?
Virtualization makes a lot of sense conceptually, but it seems that there is a LOT to consider when implementing this solution. What recommendations do you have for getting some experience?
For someone without any VM experience, what are some good resources to get started with the basics?
Virtualization makes a lot of sense conceptually, but it seems that there is a LOT to consider when implementing this solution. What recommendations do you have for getting some experience?
This article forgets to point out one of the most critical issues to think about when implementing virtualization projects: The management and performance optimization tools. VMware has some good basic managment tools, but is very weak on the performance optimization tools side. Implementing applications on virtual machines is relatively easy, but ensuring they have good performance is a major challenge. This is especially true for I/O intensive applications like databases, which if not properly implemented can bring the SAN to its knees very quickly. Check into tools like Virtual Instruments VirtualWisdom to see a best of breed solution.
Backing up your VM's in an intelligent manner can be challenging. You can save yourself a lot of time (on a restore) by backing up the 'images' of your VM's instead of their contents.
Depending on the OS used for both the host & guest, there are a few good options and a lot of questionable ones in between.
Do your diligence!
Depending on the OS used for both the host & guest, there are a few good options and a lot of questionable ones in between.
Do your diligence!
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