Even in these modern times, when lots of things are changing in the ICT world, some lessons from the past still hold true. Previously, I discussed the I/O stack in a typical database environment. As virtualization has complicated things a…
Managing Performance Expectations
Got this joke from a Dutch colleague (thanks Rohan 😉 A customer is complaining that his shiny new storage system does not perform and (as usual) blames the storage vendor. But sometimes you have to wonder if a customer uses…
Save money by virtualizing Oracle
I wrote an internal EMC memo on licensing issues with Oracle on VMware as I get a lot of questions on this topic. But I’d like to expand the question a bit. After all, my blog is named “Dirty Cache”…
Performance – The I/O stack
In my last post, I gave a highly simplified representation of “The I/O stack” of a database. In reality, it’s much more complex. I found an old picture where the whole I/O stack of a database was described and I…
The missing link in application performance tuning
When dealing with application performance problems, the quick and easy solution is often to throw hardware at the problem. Typically this is one out of processing power (CPU), memory, or more I/O resources. With a bit of luck, the bottleneck…