A Note on Coverage


This book is heavily oriented to the Solaris operating environment (up to and including Solaris 8) and Linux. However, this book emphasizes Solaris. There are a handful of reasons for this, which I would like to elucidate:

  • The majority of datacenter environments run Solaris; these environments tend to be the ones that require the most effort towards performance tuning.

  • Solaris machines tend to be more focused on performance. I suspect this is because Sun systems are more expensive than their Linux counterparts, on average. As a result, people tend to be a lot more picky about performance, so more work has been done in that area on Solaris. If your Linux box doesn't perform well enough, you can just buy another one and split up the workload -- it's cheap. If your several-million-dollar Ultra Enterprise 10000 doesn't perform well and your company is losing nontrivial sums of money every minute because of it, you call Sun Service and start demanding answers.

  • Finally, the tools available for performance analysis on Solaris are much stronger than those available on Linux. Part of this is that it's not glamorous to implement performance analysis frameworks; part is that sometimes you need to effect hardware changes to get the best performance data; part is that Linux is a relatively new operating system, developed by relatively few, whereas Solaris (and its predecessor SunOS, which provided a lot of feedback into the Solaris development process) is a rather old operating system, and Sun is a huge company. The end result is that because our ability to analyze performance problems in depth and to make intelligent tuning decisions is largely based on the data provided by our performance data-gathering tools ( otherwise , every time we tune, we're just taking a shot in the dark) it is extremely difficult to tune Linux systems. This goes directly against one major principle of performance tuning (see Section 1.2.1).

I don't mean to indicate any bias for or against any one operating system. [1] The simple truth is that serious performance tuning on Linux is a headache right now, because the tools to facilitate understanding just aren't available.

[1] In the interest of full disclosure, the author was employed by Sun Microsystems for about half the time it took to write this book.

If you are running Linux, you absolutely must download and install the sysstat package, which provides (very limited) versions of iostat , mpstat , and sar . While far from being as complete as the Solaris versions, they are at least a way to get some information. As of this writing, they can be downloaded from the author's web site (Sebastien Godard) at http://perso.wanadoo.fr/sebastien.godard/.



System Performance Tuning2002
System Performance Tuning2002
ISBN: N/A
EAN: N/A
Year: 2004
Pages: 97

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