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Mon, 22 May 2006

Bob, the Lone Sysadmin has a nice primer on logical block addressing offsets that make ESX Server work better with EMC CLARiiON storage.

Computers, being what they are, like things that come in powers of 2. Storage arrays, being computers, like getting I/O requests in sizes that are powers of 2. Storage arrays stripe the data internally in sizes that are powers of 2. 63 is not a power of 2, and because a PC uses 63 sectors per track it causes the structures the PC uses to be misaligned with the structures the array uses. And that results in more work for the array, because each I/O request from the PC ends up straddling the stripes on the array, so it has to read twice as much stuff in (two stripes instead of one).

A quick search of the VMTN Forums for LBA shows that this is a very well-known knob you need to adjust, although it really only impacts you at high levels of throughput.

(He also has some other VMware-related funny stories and pointed questions on his blog.)

posted by jtroyer at: 18:12 | | | permanent link

Fri, 19 May 2006

From Seth Livingston at Interface Clarity:

Recently I sent an email to one of the development teams I'm working with. Because of legacy organizational issues, they were slightly hesitant to adopt Virtual PC as a development tool. What follows are some of the examples I used to express how effective Virtual PC can be. These scenarios apply to any virtual machine product, including VMware.

1. For whatever reason, your development box becomes corrupted.
 
This could happen because of a hard drive crash of some kind, but it’s more likely to happen because of the pounding your box will endure while you’re developing distributed applications. Distributed applications require a great deal of server and supporting software. Further, because you’re doing development, all of this software will endure months of exceptions and process terminations.
 
There’s no better way to beat up a box than to develop distributed applications on it.
 
Hardware box solution: Spend days finding the CDs you need to reinstall all of the necessary software, including the day-to-day software and data associated with your email and Office applications.
 
Virtual “box” solution: Spend twenty minutes creating a fresh development box based on the one we’ve established as a team, another twenty minutes customizing it to your preferences, and you’re back in action.

He lists three other scenarios, all of which should be familiar to most developers.

posted by jtroyer at: 17:11 | | | permanent link

Wed, 17 May 2006

CTO Tallsails continues his story about virtualizing 18 servers on a Sun Galaxy 4200 with the technical details. He talks about picking software, hardware, storage, P2V, torture tests, and the like, but here's the payoff:

Now it's time for me to virtualize the production servers. ... I virtualized the accounting system, the email gateway, source code, the intranet, the ftp server, bug tracking system, virus scan system, Microsoft Update server and even a Domain controller with DNS, DCHP, WINS and Print Server. Here's the cool thing. Only key management folks knew we were virtualizing the servers. No one had any idea the computers they accessed and used every day were not physical servers any more. No one complained about any performance issues. In fact, some people made it a point to tell me the apps were performing better and thanked me for whatever I did.

So after this phase, I had about 8 computers virtualized. They were powered off. The UPS was out of the 90% range, the temperature was starting to drop and there was much rejoicing. But, there was more work to do. We were only running at 10% capacity. ... Now I was ready to virtualize some of the departmental servers. Theses were the ones where I would start to see the performance hit on the VM Host. There were several client/app type servers and a few small databases. I started the process. I was up to 12 vm's. Zero problems and 15% usage. I monitored for a few days then pushed on. Now I'm up to 16 vm's 18% usage. Wait, this was my limit. Only 18% usage? Wow! The UPS was in the 68% range now and the temperature in the server room was down to 73 degrees. Ok, I'm not finished yet, but I though I should slow down and monitor for a while. I monitored for about a week. Everything was rock solid. I decided to push on. ...

posted by jtroyer at: 13:17 | | | permanent link

There are fewer than 10 days left until the Ultimate Virtual Appliance Challenge deadline: May 26, 2006. It's not too late to assemble the world's most innovative virtual appliance. We're seeing lots of good entries, but you can still enter, and I guarantee that your chances are better than the state lottery. I'm serious that it's not too late -- most of the appliances are being crafted by combining open source components and packages and operating systems in clever ways. Fit & finish are important to the Challenge, but unique value and innovative use of virtualization are 75% of the judging criteria.

So if you still have that great idea kicking around that makes virtual better than real, 9 days is more than enough to pull it together. Your car doesn't need to be washed this weekend. The beach will wait. Your kid's volleyball game -- OK, go to that, but then come home and get back to work on your appliance. See the Challenge submission instructions for more information.

Our ftp servers are standing by to receive your files by May 26. You'll be doing yourself a favor if you submit it before Friday the 26th, since you'll be fighting everyone else uploading at the same time, but I don't want to nag, so just make sure you give yourself enough time. If uploading a gigabyte virtual appliance file is going to interfere with uploading your latest lipsync video to YouTube, you can burn it on a DVD and overnight it to us.

--jtroyer

p.s. the deadline to submit presentation proposals for VMworld 2006 was May 15. I haven't talked to that team, but I'd bet if you submitted one, they'd still read it. If you have any ideas for labs, or if there were any from last year you want repeated, send them my way and I'll make sure they get to the right folks.

posted by jtroyer at: 11:59 | | | permanent link

Tue, 02 May 2006

If you pre-registered with the Ultimate Virtual Appliances Challenge, you received word last week that our site is ready for your entries: instructions for entering the Challenge

If you haven't pre-registered, you can still enter the contest. Just go to the instructions and start from there. Well, start by building your appliance. It's not too late!

Our ftp servers are standing by for the mad rush at the deadline on midnight, May 26. You don't win any points by entering early, but I would bet you'll reduce your stress level by not procrastinating. And we all need to reduce our stress level, right?

All the entries will be published in early June in VMTN's Virtual Appliances directory.

posted by jtroyer at: 18:37 | | | permanent link