Skip to main content

Blogging live again!

I am returning to Google's blogger after a long hiatus. Initially, I plan to discuss a new project I have been working on -- a collection agent to gather data from several key SQL Server Dynamic Management views (DMVs) and transform that data into Windows performance counters. In a series of blog posts, I will try and make the case that generating Windows performance counters from several of these DMVs is a useful thing to do. I believe the project has the potential to help DBAs address issues in physical database design that play a pivotal role in application performance, issues that are too often ignored or, unfortunately, treated in a less than rigorous manner. I am looking to engage with other database performance professionals who have experience in this area.

Over the past several years, I have not been posting here, but instead to a WordPress web site named http://computerperformancebydesign.com/ that I own. There is a lot to like about WordPress, including superior composition tools. Unfortunately, Google's web crawler seldom gets around to that web site, so I don't see enough Readers there. As I am writing this series of posts on SQL Server performance, I will also pull some of the older material I have published on the other site.

Comments

Popular posts from this blog

“There’s a lot more to running a starship than answering a lot of fool questions.”

Continuing a series of blog posts on “expert” computer Performance rules, I am reminded of something Captain James T. Kirk, commander of the starship Enterprise, once said in an old Star Trek episode: “There’s a lot more to running a starship than answering a lot of fool questions.” Star Trek, The Original Series. Episode: The Deadly Years. Season 2, Episode 12. See http://tos.trekcore.com/episodes/season2/2x12/captioninglog.txt. For some reason, the idea that the rote application of some set of rules derived by a domain “expert” can suffice in computer performance analysis has great sway. At the risk of beating a dead horse, I want to highlight another example of a performance Rule you are likely to face, and, in the process, discuss why there is a whole lot more to applying it than might be obvious at first glance. There happens to be a lot more to computer performance analysis than the rote evaluation of some set of well-formed performance rules. It ought to be apparent by now that I …

How Windows performance counters are affected by running under VMware ESX

This post is a prequel to a recent one on correcting the Process(*)\% Processor Time counters on a Windows guest machine.

To assess the overall impact of the VMware virtualization environment on the accuracy of the performance measurements available for Windows guest machines, it is necessary to first understand how VMware affects the clocks and timers that are available on the guest machine. Basically, VMware virtualizes all calls made from the guest OS to hardware-based clock and timer services on the VMware Host. A VMware white paper entitled “Timekeeping in VMware Virtual Machines” contains an extended discussion of the clock and timer distortions that occur in Windows guest machines when there are virtual machine scheduling delays. These clock and timer services distortions, in turn, cause distortion among a considerably large set of Windows performance counters, depending on the specific type of performance counter. (The different types of performance counters are described here

Virtual memory management in VMware: memory ballooning

This is a continuation of a series of blog posts on VMware memory management. The previous post in the series is here.


Ballooning
Ballooning is a complicated topic, so bear with me if this post is much longer than the previous ones in this series.

As described earlier, VMware installs a balloon driver inside the guest OS and signals the driver to begin to “inflate” when it begins to encounter contention for machine memory, defined as the amount of free machine memory available for new guest machine allocation requests dropping below 6%. In the benchmark example I am discussing here, the Memory Usage counter rose to 98% allocation levels and remained there for duration of the test while all four virtual guest machines were active.

Figure 7, which shows the guest machine Memory Granted counter for each guest, with an overlay showing the value of the Memory State counter reported at the end of each one-minute measurement interval, should help to clarify the state of VMware memory-managemen…