Virtualization Archives

Fallacies of Distributed Computing

September 10, 2011 by Bob Plankers

I was cleaning out a stack of old papers and ran across a copy of “The Eight Fallacies of Distributed Computing” that I’d made back in 2004. As Wikipedia puts it, a guy by the name of Peter Deutsch “asserted that programmers new to distributed applications invariably make a set of assumptions… and these assumptions ultimately prove false, resulting either in the failure of the system, a substantial reduction in system scope, or in large unplanned expenses required to redesign the system to meet its original goals.” 1. The network is reliable. 2. Latency is zero. 3. Bandwidth is infinite. 4. The network is secure. 5. Topology doesn’t change. 6. There is one administrator. 7. Transport cost is zero. 8. …

How to Change SCSI Controllers on your Linux VM

September 7, 2011 by Bob Plankers

A question from Matt Vogt prompted this, where he wants to go from the BusLogic SCSI controller to the LSI Logic SAS controller. It’s actually a straightforward conversion if you have the right steps. This is based on Red Hat Enterprise Linux 3, 4, and 5, but the principle should be the same for everything. It’s basically: snapshot, change config files, change hardware. Red Hat Enterprise Linux 6, in contrast, appears to have all the LSI Logic, parallel & SAS, drivers, as well as the paravirtual SCSI drivers, so all you need to do is shut the VM down and change the type of SCSI controller you’re using. I always recommend trying this on a test VM before you try …

Official: Revisions to VMware vSphere 5 Licensing

August 3, 2011 by Bob Plankers

It’s official, VMware is changing the vRAM licensing in response to the feedback they’ve received. And, from the sounds of it, lots of feedback. They read every single vRAM post and thread in the Communities, read all the blog posts and comments, read all the feedback that was sent to them through the sales representatives and technical account managers. As they put it to me, most of the feedback was along these lines: It was less about the conversion to vSphere 5 than future growth, and the fact that the business case for future growth was drastically different now [and quite a bit more costly] than under the vSphere 4 licensing model. The new license model “introduced additional hesitation for …

Tips for VMworld US 2011 & Las Vegas

July 28, 2011 by Bob Plankers

As VMworld US 2011 approaches I’ve been thinking about the things I’ve learned about traveling to & in Las Vegas, and things that I wish I’d been told the first time I went to VMworld. You folks probably also have a bunch of good ideas that I’ll miss, please add them in the comments! Transportation: There are multiple ways for a cab to get to your hotel, but the Interstate 215 tunnel is NOT the shortest way. Ever. That’s a classic cab scam and will result in a 30 minute cab ride, when the Strip is 10 minutes away. Explicitly ask to go to your hotel via Tropicana Avenue. Traffic on Las Vegas Boulevard (“the Strip”) at night is insane, …

System Administrator Appreciation Day is One Week Away

July 21, 2011 by Bob Plankers

I have to thank the SolarWinds crew for reminding me that we, as system administrators, have a holiday coming up. And in particular, bosses, managers, and other herders of nerds should be aware that July 29th is System Administrator Appreciation Day. Yes, sysadmins. You know, those folks that tirelessly respond to pages at midnight. Those folks that come running when your CEO’s laptop has a virus on it. Those folks that virtualized all your servers and saved you lots of money. The folks that run your servers, and networks, and keep things in your data center calm and cool have a thankless job 364.25 days out of the year. Next Friday is a good excuse to thank them. Every sysadmin …

VMware Scale Up vs. Scale Out: The Big Picture

July 21, 2011 by Bob Plankers

Duncan Epping and I were kicking around the whole scale up vs. scale out argument two nights ago on Twitter, which culminated in Duncan’s excellent post on the topic. Aaron Delp also posted some numbers (and a unicorn) where he also adds the consideration for Microsoft licensing. As a Linux guy I hadn’t thought about that style of Microsoft license, and I like that a lot. While Mr. Epping was crunching numbers, so was I. I am firmly of the belief that scaling up is a better idea, because physical infrastructure and its management is not free. It isn’t cheap, either. You need to consider a lot of different things, including storage connectivity, network connectivity, KVM, power, and cooling. You can …

My Thoughts on Upgrading to vSphere 5

July 19, 2011 by Bob Plankers

I’ve been thinking a lot lately about upgrading to vSphere 5, mainly the questions of when and how I’d like to get it done. During the launch on July 12th there was a lot of talk about how many QA hours went into vSphere 5 (2 million+). That’s good news. We had some serious problems with vSphere 4 when we deployed it, bugs all over the place, vCenter crashing every couple of days, etc. VMware support wasn’t super helpful in fixing the problems because they didn’t have much experience, and they were unwilling or unable to get Engineering involved. As a result I took a lot of crap from my coworkers about my decision to upgrade things so quickly. To …

A Look at VMware Licensing & Environment Growth

July 14, 2011 by Bob Plankers

My previous post on VMware licensing changes focused mainly on the question of “will I be able to upgrade my current setup to vSphere 5?” I concluded yes, easily, and if you would like to see how I did it I encourage you to go read the post. It’s pretty obvious that futures will change, though. I’ve always subscribed to the “fewer bigger machines” theory, to which I owe a lot to Steve Chambers. Some of his writings espoused the idea that most IT failures are human error, to which I agree. Coupled with that is the idea that the cost of a server isn’t in the price, it’s in the management of it. So why have more machines, more …

The Five Stages of VMware Licensing Grief

July 12, 2011 by Bob Plankers

Update 8/3/2011: VMware announced updated licensing terms (link is to my post on the matter). As part of the vSphere 5 & Cloud Infrastructure Suite announcements today VMware announced a new licensing model. And, as expected, people are having a fit. A few of us were briefed on this new model last week, and I’ve got a four-day head start on the denial, anger, bargaining, depression, and acceptance that seems to follow this change. Let me work through it with numbers from my environment, as an IT professional, in a professional way. Hopefully this will let some people pass from the anger stage to bargaining (perhaps with their VMware sales representatives) and on to acceptance. Before I start, I do …

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