At the European Customer Conference a couple of weeks back, one of the topics was the use of DRBD. DRBD is a kernel-based block device that replicates the data blocks of a device from one machine to another. The documentation I developed for that and MySQL is available here.

Fundamentally, with DRBD, you set up a physical device, configure DRBD on top of that, and write to the DRBD device. In the background, on the primary, the DRBD device writes the data to the physical disk and replicates those changed blocks to the seconday, which in turn writes the data to it’s physical device. The result is a block level copy of the source data. In an HA solution, which means that you can switch over from your primary host to your secondary host in the event of system failure and be sure pretty certain that the data on the primary and seconday are the same.

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Pimp My Drive by Richard and Barb

There’s remarkably little information online about using MySQL on ZFS, successfully or not, so I did what any enterprising geek would do: Built a box, threw some data on it, and tossed it into production to see if it would sink or swim.

I’m a Linux geek, have been since 1993 (Slackware!). All of SmugMug’s datacenters (and our EC2 images) are built on Linux. But the current state of filesystems on Linux is awful, and …

whenever i see somebody’s list of essential mac applications, i am always a little surprised at how little overlap it has for me. now that i’ve mostly switched over the new macbook pro, here’s the list of applications that i have installed:

• acorn ($50): this is a nifty little image editing application. in the last few days, i have been using it to mock up shelving layouts for the store.
• bzr (free): this is the distributed version control system of choice at mysql these days.
• busysync: it would be nice to keep my google calender and ical in sync. after giving spanning sync a try for a bit, i am giving this a try as an alternative.
• …

to build connector/odbc 5.1 on mac os x leopard, the first thing you will need is xcode. then you will want to install a recent version of mysql (5.0 or 5.1, or even 6.0 if you are feeling adventurous).

to be able to build the gui setup library, you will need to install qt, but i have found it easiest to work with qt3, not the latest qt4. you can download the last release of that from trolltech’s ftp server — the file is called qt-mac-free-3.3.8.tar.gz. you will need to apply this patch to allow it to compile on leopard. i configure it with some options to eliminate stuff i don’t care about, and to build statically:

./configure …

working with the iodbc driver manager on mac os x has been a frustration on two fronts.

first, the installer api functions provided by iodbc constantly set the configuration mode to ODBC_BOTH_DSN, which means you have to keep resetting it to the correct value after nearly every installer api call. this problem is platform-agnostic — the iodbc code is just plain wrong.

second, when called from the odbc administrator application on mac os x, any failures that the driver reports or passes through from the installer api in registering the driver are ignored, and the application instead uses a generic prompt for dsn configuration.

so even with the first problem fixed, the second problem has led to a lot of tail-chasing until i discovered that the odbc administrator application only obtains enough privileges to write to /Library/ODBC as …

Just recently I seem to have noticed an increased number of mysterious crashes and terminations of applications. This is generally on brand new systems that I’m setting up, or on existing systems where I’m setting up a new or duplicate account.

Initially everything is fine, but then all of a sudden as I start syncing over my files, shell profile and so on applications will stop working. I’ve experienced it in MySQL, and more recently when starting up Gnome on Solaris 10 9/07.

Sometimes the problem is obvious, other times it takes me a while to realize what is happening and causing the problem. But in all cases it’s the same problem - my TMPDIR environment variable points to a directory that doesn't exist. That's because for historical reasons (mostly related to HP-UX, bad permissions and global tmp directories) I've always set TMPDIR to a directory within my home directory. It's just a one of those things I've had in …

I’ve been investigating some recent issues with installations of MySQL on Mac OS X and the Perl DBD::mysql module for accessing MySQL from within Perl through DBI.

The problem exists only with binary distributions of MySQL and is related to the installation location of the libraries for the MySQL client that DBD::mysql uses.

By default these are installed into /usr/local/mysql/lib, but the dynamic libraries are configured to be located within /usr/local/mysql/lib/mysql.

It’s possible for DBD::mysql to build and link correctly, but trying to use the library will fail because it can’t find the library in the latter directory, even though it linked to the library in the former location. To get round this, the easiest method is to create a link within the directory that points to the parent. For example:

$ cd /usr/local/mysql/lib
$ ln -s . mysql

That …