DBA Lounge

ASM multi-disk performance

If you have the ability to combine disk spindles at both the SAN level and Oracle (ASM) level, which one is better? Should you combine all your spindles on the SAN and present 1 big disk to OS and give that to ASM? Or should you present each individual disk spindle to ASM and let ASM do the mirroring? The disk group with 2 disks is slower! Those results are consistent, and confirmed with diagnostic output from iostat. You may start to wonder why would 2 be slower then 1. It should be twice as fast!

IT Industry Trends Towards Anti-Certification

Did anyone else notice this interesting e-week article titled The Downside of Certification? It immediately reminded me of an article written by Pythian team lead and datawarehousing architect Rob Hamel titled “Get Down with OCP: Evaluating DBA Job Applicants in an OCP World”. What Rob noticed in 2004 was that certification can mask a certain type of incompetence from a casual technical evaluation process.

Oracle Finally Documents lnnvl() in 10GR2

Tip of the hat to Eddie Awad who does some noticing and some digging to confirm that lnnvl(), a function that provides functionality similar to ANSI “Is Not True” and can be used to return boolean TRUE whenever the predicate to the function is either NULL or FALSE is now supported in 10GR2.

Day two at Collaborate 2006 (Babette)

I skipped the general session but heard there was talk about Oracle unlimited support. Basically someone else summarized it as Oracle will take your money as long as you want to give it to them. So no more “de-supported” products. Of course, old products will not get bug fixes unless you really really really pay for it.

Day two at Collaborate 2006 (Christo)

After I actually woke up I found myself attending a session about LogMiner by Chet Watmough. Log Miner in my opinion is a vastly under-used utility. It has such great versatility. Chet showed some techniques to add additional logging. By inserting the client info information into a dummy table, just to produce a record in the redo stream, he can identify who did what.

First Day at IOUG 2006

So I made my decision and went to “RAC & ASM best practices” presented by Kirk McGowan of Oracle. I wanted to see how far the documentation / common sense was from what will actually work. It wasnt that far from the docs, which is good. It means Oracle got it right.

Good Luck at Collaborate ’06

Good luck to Pythian DBAs Christo Kutrosky and Babette Turner-Underwood who are presenting at Collaborate ’06 today and tomorrow. These are two outstanding presenters with deep technical knowledge reinforced with day-to-day use of the technology and I would encourage anyone to attend. If you attended the presentation, by all means post any feedback here!

First day sessions at Collaborate 2006

I got in today and missed the General session … because I did not get here in time and still had to register. . . . I started the morning with an Oracle session on RAC. It was a two-part session and I did not have the patience to wait out the first half. It was on best practices and I was looking for something more technical.

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