Archive for October, 2009

Virtual Hardware 7 Bug, Woeful VMware Response

October 29, 2009

UPDATE This post is actually woefully inaccurate – go read this one instead!

I don’t like making posts like this, really i don’t. As much as I’ll sing the praises of VMware ’til I can’t sing no more, I’ll also point out the shortcomings – I don’t turn a blind eye just because I like the company.

Recently in the course of doing some vSphere testing, we came across some rather strange behaviour. When creating a new Windows Server 2008 VM with Virtual Hardware 7, the LSI SAS Adapter, and 2 virtual disks, we found that the second disk was being offlined during Windows installation. Even more strangely, this only seemed to effect Server 2008 Enterprise, both 32 and 64bit. Standard edition worked fine.

That being the case, and knowing that there was no differentiator between Standard and Enterprise edition from the VMware side (unlike with 2003, which has separate options in the Guest OS dropdown), I presumed this must be some wierd Microsoft problem. So we logged a call with Microsoft, only to have them come back and say the code base is the same so they didn’t think it was them. Microsoft asked if we could log a call with VMware about it, which we duly did.

And got pointed to this VMware KB article.


VCP4 Exam Post Mortem (Yes, I Passed :)

October 27, 2009

Pretty sneaky of me to post my thoughts on the exam material the night before sitting the exam eh? Well, not really, but at least I’m not going to make you all anxiously wait for the follow up post like I know you were. C’mon, I know it. Seriously. Somebody was. Other than me. And for anyone who cares for the details, it took me just over 30 minutes to finish and I scored a few points shy of 400.

I’ll attempt to walk the fine line of providing something sufficiently vague to sidestep all the exam legalese, yet meaningful enough to be of assistance to those who intend on taking the exam. In order to do that, I’m going to be fairly brief (for a change).

First of all, strategy. The exam is entirely multiple choice, and I stick to a time tested strategy of “you either know it or you don’t, and the first guess is usually the best“. I don’t believe in reviewing multiple choice exams – like I said, I either know the answer or I don’t. If I do, what’s the point in reviewing it? If I don’t, whats the point in having second or third guesses? This is how I finished the exam in ~30 minutes, and it’s been the same story for every multiple choice exam I have sat in my life.

VCP4 Exam Preparation…

October 26, 2009

I hate exams. Or rather, I hate the type of exam that is typified by pretty much all the IT certifications I’ve bothered to attain over the years. In fact I hate them so much, the only thing stopping me from swearing right now is that I don’t want to get John in trouble (again). And yet I feel so compelled to sit them. Ah, the mysteries of life.

It’s been a good while since I’ve read the VMware documentation cover to cover… in fact the last time I did so was for the VCP3 exam a few years back. This time around there are a few things that jump out at me (maybe I’ve just forgotten what the old docs were like, maybe not), which has led me to making a few assumptions about what is worth studying for the exam. Most notably, the use of the command line.

Finally, A Black Swan

October 11, 2009

Anyone who has read Nassim Nicholas Taleb‘s work will know the story of the black swan. In a nutshell, the story goes that up until about 220 years ago, the Olde World thought that all swans were white. The basis for this was of course purely empirical – out of the millions of confirmed swan sightings over many hundreds of years, every single one was white. Until the discovery of Australia that is, when a proposition with hundreds of years of supporting data was instantly invalidated with the first sighting of a black swan. And so Taleb coins the term “Black Swan” (note the capitalisation) to describe a phenomenon that is an outlier (in the statistical sense), that has extreme impact, and is treated in retrospect as predictable.

And so Danger‘s massively public data loss last week can be considered a Black Swan. Already the ignorant are calling it a failure of the cloud as a model, or reporting it with such gross simplicity that it makes an infrastructure guy like me want to start punching things (mainly the so called “tech” reporters who have penned such articles). And I have no doubt that whatever the root cause is, it will in retrospect be deemed as predictable so that people can have warm fuzzies about “the cloud” once more, knowing that such things couldn’t happen again because we now know how to identify and mitigate such things in advance. Just like the recent economic crisis.