Memory Overcommitment. Bluff or Real Requirement?

In my humble opinion, yes, it does. Now let me explain why.

As a real world example, you guys have us, WTSLabs. When we decided to move to a virtual world, I personally looked at most of the offerings available: Microsoft Hyper-V 2008 R2, Citrix XenServer and VMWare ESXi (considering our size, free would do the trick for us for sure). The deciding factor that took us down the VMWare ESXi route was the simple fact it can overcommit memory.

Once you look at how our VMs were performing, most of the time these were sitting idle, consuming few resources (that was the case with our environment – your environment may be completely different and in that case overcommitment may not be for you).

No matter what anyone else says, if you all remember, years ago one of the main driving factors (or sales pitch if you will) towards virtualization was to consolidate your X physical servers into a bunch of physical hosts. I remember seeing several times Sales/Pre-sales guys going to offices explaining that most of the time the customers servers were there doing nothing and thanks to that, bringing all these ‘idle’ servers under one single host was possible.

I am not saying that is the case with any server and/or any environment. For sure there are several SQL, Exchange boxes out there that are always being hammered, working hard. But for tons of companies out there, especially in the SMB market, it is almost guaranteed that is not the case.

Back to our own scenario here, we now run 6 VMs. The resource hog one is our Exchange 2007 SP2 box (what a surprise…) setup with 4GB. Then we have one domain controller, web server, TS (running Windows Server 2008 R2) and two XP VMs. By monitoring these up and running on a regular day they are indeed idle most of the time, not using many resources. I do not remember all the numbers but I know we are overcommiting memory but not by a lot (probably one to two gigs – our Dell Server has 8GB).

Like WTSLabs there are many other companies out there on the same boat. And for these, if you cannot overcommit this may mean buying another server. For large enterprises another box may be just a drop in the ocean. Not for us. 🙂

Performance wise, nothing to complain so far; everything works great and seems responsive. To me, the reality is there will be cases where overcommitment is indeed not a good idea and there could be performance issues if used. But on the other hand, there will be way more cases where overcommitment will not be an issue and everything will work great, saving companies money.

The reason why Microsoft and Citrix as of today downplay memory overcommitment and all the technologies behind it (you can read more here) in my mind is simple: they do not have it.

Will they add that? I am pretty sure they will and if they do there will be two possible reasons for that:

1. They added a feature they consider useless just because they are right and the world is wrong.
2. Added it because it is really important and useful.

I will go with the second option. And once they do it I may take a look at Hyper-V and XenServer again for our needs.


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Full speed ahead

Ok. I can finally say we are now all set and ready to take orders.

When you are a small operation (and yes, that is the case at WTSLabs; only three people as of today) everyone is supposed to do everything. You guys should thank our CEO for getting the website, forums and the blog up and running (that would be me by the way). All I can say is I am tired of PHP, MySQL and Windows Server 2008!

But at least we now have a real company setup and my next task, as several people noticed when trying to reach us at 1-877-WTSLABS, is to get the freaking phone system up and running. This should be done hopefully during this sunny, warm and GREAT weekend ahead of us. Probably the first great weekend this spring. On top of that I have to sand my deck so my wife can stain and seal it. Phone or sanding? Easy pick for me.

Back to the topic, I really just wanted to say we are now full speed ahead and our two initial products, WebTS and AudioTS are finally out. The problem is, if you guys do not download and give them a try we will never know what you think and more than that, may not be around for long. So please go ahead and take a look at the products. Once that is done, always feel free to contact me directly for feedback, suggestions, complains, anything. As with all my companies I do think it is critical to always have an open channel between the management team and our customers. And by that I do not mean an ombudsman or some obscure email address.


I mean get the phone and call me. I can guarantee I will call you back.



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