VM stories: VM makes memory testing easier and faster

VM stories: VM makes memory testing easier and faster

Summary: With the VM solution, it's possible to have and test a theory, no muss, no fuss, and no hassle. All in about 10 minutes.

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I've been making more and more use of VMs as part of the migration process for my old CMS to a new environment. Here's one story where a virtual machine made life a lot easier.

I had two virtual machines running on my server and ran into a bottleneck with one that I might could be solved by giving it a LOT more memory.

So I temporarily shut down the other VM on the server, loaded the problem one up with all the memory possible, and tested. As it turned out, lots of RAM didn’t fix the problem. So I deallocated the memory, gave it back to the other VM and brought it back online, and went looking for a different solution.

By using VMs, I was able to give the server a quick, huge increase in RAM remotely, in about 10 minutes.

It's important to understand that my servers are in Illinois, while I'm in Florida. By using VMs, I was able to give the server a quick, huge increase in RAM remotely, in about 10 minutes.

If my problem server was running as just a physical machines, that RAM increase would have involved a call to the ISP, begging them to purchase more RAM, waiting for them to do it, waiting for it to arrive, shutting the machine down, pulling it out of the rack, opening it up, installing the RAM, putting it back, booting it back up, and -- still -- it wouldn’t have been fixed.

I’ve had to diagnose hardware the old-school way before and it probably would have been at least two weeks before I was able to run my test, not 10 minutes. Plus, I would have probably had ten or fifteen interactions with my ISP, had to call in a few favors, probably had to explain myself three or four times, and justify my reasoning.

With the VM solution, I had a theory and was able to test the theory, no muss, no fuss, and no hassle. All in about 10 minutes.

Topics: Virtualization, Servers

About

David Gewirtz, Distinguished Lecturer at CBS Interactive, is an author, U.S. policy advisor, and computer scientist. He is featured in the History Channel special The President's Book of Secrets and is a member of the National Press Club.

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  • That's why I love VM...

    I work with ESXi 4/5 on my datacenter... it's fantastic... We have a hundred servers, from which 90 are VM's, the hardware involved is no more than 33 physical host servers. The consolidation rate vary a lot depending in the server workload, but our maximum is 16 VMs in one machine. No way IT can live without virtualization any more.
    erick.mendes