Tuesday, March 20, 2007

Overview of Virtualization Performance

As the Guest Editor for this month's MeasureIT e-zine on the topic of virtualization, a compliation of articles is presented from both earlier MeasureIT authors as well as some papers from the CMG conference proceedings. Titles include:

  • Visualizing Virtualization

  • It May Be Virtual - But the Overhead is Not

  • A Realistic Assessment of the Performance of Windows Guest Virtual Machines

  • Measuring CPU Time from Hyper-Threading Enabled Intel Processors

  • Hyperthreading - Two for the Price of One?

  • To V or Not to V: A Practical Guide To Virtualization

  • The Virtualization Spectrum from Hyperthreads to GRIDs

This issue of MeasureIT is unique in my mind because it is rare to find, in one place, such a broad collection of performance perspectives centered on the intensely hot topic of virtualization.

Friday, March 16, 2007

Pushing the Wrong End of the Performance Pineapple

In case you're wondering why you, as a performance analyst or product manager, don't get much traction in your shop when you try to proselytize the otherwise highly rational notion of designing performance into the product (as opposed to patching it in after it has been released), contemplate this:

The performance of the production process trumps the performance of the product it produces.

If you don't read and heed this concept, you are going to find yourself perpetually frustrated. What I mean by this is, that we (performance weenies) are focused on the speeds and feeds of the bits and bytes associated with the technology being produced, whereas most companies these days are forced by Wall Street to be more focused on the performance and cost of their internal management processes.

I said the same thing on page XX of the Preface to my 1998 book, The Practical Performance Analysts:

"Management no longer focuses on the speed of the product as much as the speed of producing the product. Nowadays, production performance matters more than product performance."

I believe this is truer today than it was 10 years ago. Here are some reasons why:

  • Many hi-tech companies have offshored their engineering while keeping middle and upper management local. Latest example: Google goes to Poland

  • There are substantial tax incentives for USA companies to go offshore, and then ask Congress for more H-1B visas

  • There is a financial incentive to charge the customer (possibly you) for performance upgrades

  • The Dilbertization of the IT workplace

Is it any wonder then, that you don't get a warm reception from upper management? The odds are stacked against you, and the stack goes all the way back to Wall St. Don't even think about fighting that war. The only battles worth fighting, in my view, are the ones that employ guerrilla-style tactics.

Ironically, as I explain in my classes, this is where performance analysis really started, viz., with Frederic Winslow Taylor, the original performance analyst (anal-ist?) who introduced "time and motion" studies on human production in assembly lines and office environments of the early 1920s.

Oh, in case you're wondering about the title, it's an Aussie-ism. There is no good or smooth end of a pineapple.

Tuesday, March 13, 2007

PDQ geht Deutsch

PDQ goes German! Well, perhaps PDQ gets discussed in German, is a slightly more accurate description. The latest issue of Linux Technical Review (a German publication) discusses performance monitoring, in general, and how Perl::PDQ, in particular, can be used to go beyond monitoring to performance prediction, without breaking the bank.
The article is entitled "Berechenbare Performance" and the Abstract says: Wo man mit Statistik allein nicht weiterkommt, erlaubt es die Performance-Simulation beliebige Was-wäre-wenn-Szenarien durchzuspielen. Ein Perl-Modul hält den Aufwand in Grenzen.

How's your German? Kaput? Maybe Google can help? The appearance of the word 'simulation' in the Abstract is inaccurate, but maybe something got lost in translation.

PDQ Version 4.2 Released

PDQ (Pretty Damn Quick) finally made it out the door as version 4.2 and is now available for immediate download. The PDQ models included in the /examples/ directory correspond to those discussed in each of my books, but PDQ is primarily associated with the Perl::PDQ book.

The main features of PDQ 4.2 are:

  • Java version of PDQ contributed by Peter Harding in Australia

  • PHP version of PDQ contributed by Italian student Samuel Zallocco

  • Threaded-server model and errata corrections contributed by Neil Gunther

  • Better organization of the Perl and Python models

  • The Java and PHP packages are released stand-alone at this time

Complete installation instructions are available on the download page. Make sure you also read the various README files. Tom Becker (USA) and Christof Schmalenbach (Germany) have kindly provided separate installation notes for ActivePerl on Windows. This also indicates how international PDQ has become.

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Tuesday, March 6, 2007

Hotsos 2007 Sizzled!

Just returned from Dallas where I was an invited speaker at the Hotsos 2007 Symposium on ORACLE performance. This symposium was a class operation: great hotel, great people, great food, great presentations, etc. and, as a newbie, I was treated very well. It seems that Cary Milsap (the energy behind the symposium) had already greased the runway for me, so I found myself to be a known quantity to many of the attendees, even though I had never met them before. This was way cool (Thanks, Cary).

Although ostensibly a group of very enthusiastic ORACLE performance people (about 450 attendees), they are not bigots, so they are interested in all aspects of performance. Moreover, Oracle performance gets critiqued. Capacity planning is one aspect that is new for many of them and I was a member of a panel session on that topic. During the 24 hours I was there, I attended a very interesting session on the measured limitations of RAC 10g scalability for parallel loads (ETL) and queries against a large-scale data warehouse (DWH), and a talk on how data skew can impact the kind of performance conclusions you tend to draw. But perhaps the most interesting things that I learnt came out of several spontaneous discussions I had with various folks, including some conversations that went into the wee hours of Monday morning. My only regret was that I couldn't stay longer. I definitely plan to attend Hotsos 2008.

Thursday, March 1, 2007

Disk Storage Myth Busters

Interesting myth-busting synopsis on disk drive technologies entitled: "Everything You Know About Disks Is Wrong" over at StorageMojo. Some of the key myths busted by extensive research at Google and CMU include:

  • Disk drives have a field failure rate 2 to 4 times greater than shown in vendors specs.

  • Reliability of both cheap and expensive drives is comparable.

  • Disk drive failures are highly correlated, thus violating one of the assumptions behind RAID Level-5.

  • Disk drive failure rates rise steadily with age rather than following the so-called bathtub function.

Storage vendors such as NetApp and EMC have responded. David Morgenstern asks in eWeek, why would anyone have trusted the MTBFs that appear in vendor glossies in the first place?

Background on failure rate analysis can be found in Chapter 1 of my Perl::PDQ book entitled: Time - The Zeroth Performance Metric.