Pythian Goodies: Oracle Disk I/O Basics

Posted in: Technical Track

Two weeks ago, I released a video about Flash Recovery Area as part of the Pythian Goodies project. Here is the next video in the sequence.

Oracle I/O Basics

This video covers:

    • Disk I/O Concepts
    • Async disk I/O concepts – when does Oracle use it
    • Monitoring via vmstat – explained
    • Monitoring via iostat – explaining the meaning of the %util (disk busy time) column, queue depth, service time, wait time
    • Concepts of larger queue, faster disk I/O, slower response time, more through-put.

As usual, the Goodies are intended to be debates, so please post any questions of follow-ups with the relevant time-index from the video.

N.B.: YouTube decided to limit director’s accounts to 10 minutes and decided to have a new account type called the “10+ minutes” account. Unfortunately, the form to apply for such accounts is disabled until further notice. We had to find an alternative and we picked veoh. It comes in handy as it offers an iPod version for direct download.

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About the Author

An Oracle ACE with a deep understanding of databases, application memory, and input/output interactions, Christo is an expert at optimizing the performance of the most complex infrastructures. Methodical and efficiency-oriented, he equates the role of an ATCG Principal Consultant in many ways to that of a data analyst: both require a rigorous sifting-through of information to identify solutions to often large and complex problems. A dynamic speaker, Christo has delivered presentations at the IOUG, the UKOUG, the Rocky Mountain Oracle Users Group, Oracle Open World, and other industry conferences.

6 Comments. Leave new

good stuff here, folks.


Not impressed with veoh. It looks like I need to have Windows/Mac, note NO LINUX, to download and view file and I have to use some Veoh player. I appreciate Pythian taking the time to produce these videos for the Oracle community but I would request that the distribution method also support *nix users.

I’ll crawl back to my Web 1.0 world.



Hmm – that’s strange. Did you try downloading the ipod-compatible one, if you have an ipod? It’s in an open format that video players on linux should be able to easily view.

Also – I am confident that the flash player works in linux – is this only an issue when trying to download it to view it offline?




I can confirm that the Flash player works with Linux, Ubuntu 6.10 to be precise. Shockwave Flash player = 7.0 r63.


“Veoh is no longer available in PARAGUAY. If you are not in PARAGUAY or think you have received this message in error, please go to and report the issue.”



It says “download Veoh for complete view” but still it doesn’t work. I downloaded Veoh software and lost my FF bookmarks. Even NOD32 keep warning during the installation process too!

Bad bad Veoh.


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