Tag Archives: ourdelta

Book: Pro Linux System Administration

Peter Lieverdink (also known as cafuego on IRC/identi.ca, engineer on OurDelta builds and for Open Query) has co-authored a book that’s available since Monday. The title is Pro Linux System Administration published by Apress.

These days some people don’t want to bother with system administration, and either hire or outsource. Others want to find out more and do things themselves (home and small office use), and that’s the intended audience for this book.

Measuring HD latency in ways relevant to MySQL

As I described yesterday, Open Query is doing some tests on SSDs and other devices pretending to be harddisks (SANs, battery-backed RAID controllers, etc). To aid this, I wrote a small tool to test the different kind of I/O operations MySQL would/could do, which is not quite the same as what other general purpose apps would do, and also not what other test tools measure. For instance, it tries Direct I/O as well as fsync() after each write, and also it a range of different I/O block sizes.

In a nutshell, it’s aimed to do what MySQL does, without MySQL! Testing lots of different setups for this particular purpose (even with fantastic tools like MySQL Sandbox) is a complete pest, and changing InnoDB page size requires a recompile. While Percona has tried a larger page size in the past and decided it wasn’t worth it (the default is 16K), I thought it worthwhile to include such a test as the situation may change over time with different devices.

So, this is a little tool for a very specific purpose, and it should not grow beyond that – but do feel free to abuse it for whatever other purpose you reckon fits a similar approach. Oh, and it outputs CSV for easy graphing. To grab the code, go to the hdlatency project on Launchpad. It’s plain C, and GPLv3 licensed.

The problem with April Fools in the MySQL/web space…

…is that truth is stranger than fiction. Reality does not appear any more plausible than plain nonsense.

We were discussing this yesterday on #ourdelta (Freenode IRC) in the context of How MySQL really executes a query by Baron. Antony Curtis noted that if he’d write a truthful post on that topic, people would think it was made-up regardless of the day of the year!

Another proof of the premise: Baron has now put a giant banner above/below his post, explaining that it was a joke. Apparently that’s necessary?

I tend to come up with neat ideas for April Fools throughout the year, neglect to write them down, and come the day I have a blank. But, given the above, there’s another option: you just write a truthful story, still leaving people wondering whether it’s for real. I reckon the main issue is probably with the rest of the year, where lots of people still write nonsense, and the truth remains weird as usual. At least on April 1st you know to question. I hope.