Master-Master Replication With MySQL 5 On Fedora 8

This document describes how to set up master-master replication with MySQL 5 on Fedora 8. Since version 5, MySQL comes with built-in support for master-master replication, solving the problem that can happen with self-generated keys. In former MySQL versions, the problem with master-master replication was that conflicts arose immediately if node A and node B both inserted an auto-incrementing key on the same table. The advantages of master-master replication over the traditional master-slave replication are that you don't have to modify your applications to make write accesses only to the master, and that it is easier to provide high-availability because if the master fails, you still have the other master.

Last week I uploaded MySQL 5.0.51a-1 to Debian unstable. Usually not worth a separate blog entry, but in this release I included the patch for MySQL bug #4541, which was opened more than three years ago. The problem results in an error like this, e.g. when migrating a database from latin1 to utf8:Specified key was too long; max key length is 1000 bytesThe patch from Ingo Strüwing now included in Debian raises the maximum key length to 4005 bytes or 1001 UTF-8 characters. It will not go into the official MySQL source repositories because it results in bigger buffers and as such increases memory footprint and decreases performance. See the bugreport for further details.

Update: After some criticism …

Since I wasn’t really blogging back then, I forgot to mention that Alert Logic received a great review at Security Magazine in its April 2007 issue. We got a “Best Buy” rating when compared against some of our competitors.

We were all very proud of the new releases of Threat Manager over the past year, so it was very good to be recognized for the work. A perfect score, no less! All 5 stars.

Velocity is the new O’Reilly conference aimed at discussing topics related to scaling web sites and applications on the Web. It seems really interesting, and I will try to attend.

Having access to some of the industry’s experts in scaling web sites will be really useful. In fact, Steve Souders is one of the program chairs of the conference, and he is also known as the creator of the very popular YSlow extension to Firefox.

Ok folks, just after testing out some new changes to this week’s release - I’ve uploaded a new version. Here are the following changes:

Changelog 1.2a
- changes line thickness to 1 for all graphs, 2 was too thick for running at 5 minute intervals for the poller
- added several scripts for running and logging monitor agent and report_generator
- changes talkback sripts to one script instead of 3

Today was at the faculty of Industrial Design in Delft to attend the first 'c,mm,n Garage' event. c,mm,n - pronounced as common - is a project to develop sustainable mobility. It is led by Stichting Natuur en Milieu, The Netherlands Society for Nature and Environment and currently the main participants are students from a number of Dutch technical universities.

Right now, engineering efforts are focused on a clean, remanufacturable car that runs on electricity generated by a hydrogen fuel cell:
The car is almost completely built out of biodegradable plastics, making it extremely light and environmentally friendly.
There is a YouTube Video available that shows off the exterior design and which gives you a good impression of how open and …

The problem

Hands up those that don’t monitor their production MySQL web server. I’m a little surprised by this, but I’ve visited several clients that have absolutely no monitoring other then “the customers will tell us when something is wrong”. The lack of system monitoring is one of the topics in my book “101 ways to screw up a successful startup”.

Why is monitoring important? First it can tell you when something is wrong, most monitoring systems introduce some level of constraints that trigger notifications via email, SMS or red flashing screens. Second, and I consider more important, is it allows you to analyze change and compare results over time. Let’s say you added more memory to your server, and then remembered to also increase the MySQL buffers appropriately. How much improvement did it make? Rather then “it seems faster”, you can have hard and fast numbers to back it up.

The …

Over the last several weeks I have been testing out the 2 mtron drives that easy computing company provided me. In fact I have been testing like a madman. Nightly I would kick off a batch of DBT2 tests, sysbench tests, bonnie++, and more. Each test changed something about the environment I was testing. RAID 1, RAID 0, with easy’s MFT, without the MFT, with the logs on SSD, With the logs on a raptor drive, etc. Each test run when it completed successfully would take roughly 12 hours. a typical example of a portion of one of these test runs is:

shutdown mysql
remove the data and log files
wait 5 minutes
startup mysql
wait 5 minutes
load a 200 warehouse DBT2 test
wait 5 minutes after the load is complete
run DBT2 test

rinse and repeat.

Minimally I have been doing a 40 active warehouse dbt2 test and a 60 active …