Virtualization

Align Your Partitions

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This is post #1 in my December-long series on Linux VM performance tuning, Tuningmas. I wrote about it back in 2006, and lots of others have written about it since (Duncan Epping has a nice vendor-agnostic post with diagrams): misaligned storage trashing your I/O performance. What’s the big deal? In short, it is killing your I/O performance. Logical Block Addressing on your disk drive makes the Master Boot Record 63 bytes long. This means it occupies sectors 0-62 on disk, and the first partition will start at sector 63. The number 63 is a persona non grata in the computer world. It isn’t a power of 2, and it certainly doesn’t line up with your storage’s idea of the world …

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A Little Transparency Helps

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In my past I’ve been a theatrical lighting designer. I’m not professionally trained, I just sort of picked it up by working with community theater groups. A friend who is a professionally-trained lighting designer once gave me a tip about darkness, in one of those situations where I was trying to illuminate only a small part of the stage for a particular scene: “Always leave some light on the rest of the stage. Humans get curious about what they can’t see, and they won’t realize it but they’ll spend a bunch of time watching the absolute darkness instead of what you want them to watch.” When I light a show I usually have some general “down” light available, so the …

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Thoughts on the VMTN Subscription Idea

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Mike Laverick has started something of a campaign to bring back the VMTN Subscription, which was something like the Microsoft TechNet or MSDN models. I’m a TechNet subscriber and for $349 I get access to most everything Microsoft has. For testing purposes this is great. I don’t have to spend a lot of time dealing with activation timeouts, I can just test things and leave the my own test environment up and running for when I want to test new VMware Tools, or whatever. I think that’s fair, since I buy real Windows licenses for every other VM that I have (dev, test, QA, production, etc.). Right now, if you want a test environment your options are to pay for …

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Why Does My Linux VM's Virtual NIC Show Up As eth1?

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Got a Red Hat Enterprise Linux (or CentOS, or Scientific Linux, or Oracle Enterprise Linux, etc.) 6 VM that won’t bring up it’s single network interface after you clone it? Get the following error when you try using /sbin/ifup to enable it? “Device eth0 does not seem to be present, delaying initialization.” When you use “/sbin/ifconfig -a” you see eth1 where eth0 should be? eth1      Link encap:Ethernet  HWaddr 00:50:56:9B:00:85             BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:812 errors:0 dropped:0 overruns:0 frame:0           TX packets:214 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           RX bytes:72509 (70.8 KiB)  TX bytes:28324 (27.6 KiB) lo        Link encap:Local Loopback            inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:16436  Metric:1           …

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Cargo Cult System Administration

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The term “cargo cult” comes from World War II, where the USA and Japan created small airstrips and bases on islands in the Pacific Ocean, and the locals mistook the cause & effect in relation to why goods and cargo appeared on the island. It’s absolutely fascinating, and the Wikipedia entry for cargo cults indicates some of these cults are still operating. The excellent book Code Complete, by Steve McConnell, introduced me to the idea of cargo cult software engineering. Turns out, a guy by the name of Eric Lippert coined the phrase “cargo cult programming,” and explains the whole thing well: During the Second World War, the Americans set up airstrips on various tiny islands in the Pacific.  After …

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How To Power Your Stuff While You're in Copenhagen

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Denmark’s power is 230 Volts and 50 Hz, which means that if you are traveling from a country with another power specification (like the United States, at 110 Volts and 60 Hz) you have some considerations to make. Last year when I was there for the VMworld conference I had my Dell laptop, my iPad, my iPhone, and my Nikon D80 digital SLR camera. I left my electric razor at home; devices with motors in them need step-down transformers so they don’t catch fire. Step-down transformers are heavy and annoying and have fuses that blow. I can shave with a disposable razor for a week, no big deal. I planned to charge my iPhone off my laptop’s USB, thereby saving …

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Who Cares About Time Zones Anyway?

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If you think you have a thankless job you should think about Arthur David Olson and Paul Eggert. Heck, it’s not even a paying job for them. They’re volunteers. Perhaps even masochists. What do they do? They maintain the time zone database (“zoneinfo”) for all of the computing world. And while residents of a particular country have to put up with just the general stupidity of their own politicians, these guys have to put up with all the stupidity of all politicians, across the Earth. Every time a politician in Russia, or Cameroon, or Indiana thinks it’d be a good idea to screw with the clocks these guys update and redistribute their database[0]. Vendors pick up the update and send …

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How to Install Microsoft SQL Server 2008 R2 for VMware vCenter 5

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My venerable post on installing MS SQL Server 2008 for vCenter 4 was getting old, so I thought I’d update it, if only because I have a new admin helping me and I’m going to stick him with doing a bunch of installs. Ha! I thank the VMware folks who have incorporated a lot of the tweaks from my original document into the defaults for vCenter 5. They were probably obvious, and not taken from my work, but it’s content I don’t need anymore. Awesome. While I don’t mean this page to become a general support site for vCenter SQL Server installations please leave a comment if something needs to be clarified or corrected, or if I’m doing something dumb …

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Yak Shaving

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One of my favorite terms for my day-to-day work life is “yak shaving,” and I’m saddened that so many people have not heard of it when I say it. “What are you doing today?” I’m asked. “Shaving yaks,” I reply. Coined at MIT as part of the Computer Science and Artificial Intelligence Lab (CSAIL), it’s described well in Jeremy Brown’s archived email: You see, yak shaving is what you are doing when you’re doing some stupid, fiddly little task that bears no obvious relationship to what you’re supposed to be working on, but yet a chain of twelve causal relations links what you’re doing to the original meta-task. Similarly, the Jargon File has it as: Any seemingly pointless activity which …

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8 Things I Really Like About VMware Workstation 8

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I’ve been using VMware Workstation 8 for a few days now. I really like it. A lot of posts have been made hitting some of the major highlights, but there are hundreds of small improvements that add up to be a big deal for me. Here are eight. 1. You can connect to a vSphere setup, and upload your VMs into the server environment. I’ve already used it to set up a new VM template locally, then upload it to my production environment. As I get more into vCloud Director I anticipate using this heavily to set up templates for new (or old) OSes. It’ll also be a great solution for dealing with virtual appliances that make assumptions, like DHCP. …

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