With Ganglia, graphing a large number of servers has never been so easy... Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids. Ganglia let you create any kind of module in C/C++ or Python. You can also use the command line tool Gmetric and then the scripting language of your choice. The problem with Gmetrics is that you can’t keep your data organized by group and it’s getting harder to poll values in an efficient way. Few months ago I needed to monitor some JMX values returned by a Java daemon.
The "Security sandbox violation" message is a common problem for any Flash developer who try to do a Snapshot of an RTMP Stream. There was a couple of workaround but they stopped working since Flash Player 9.0.115 as it was considered as a possible bug. So, now how to do a proper snapshot of an RTMP stream ? The answer is simple but you’ll need to have the control on the streaming server, whatever it is FMS or Red5.
My previous post was made a long time ago, so here is a draft that I finally decide to post. Let’s see how to secure some of your data with an encrypted block device using losetup and dd.
Steps will be :
- Create an image with dd
- Build a new device using the image with an encrypt algorythm by using losetup
- Format the device using mkfs.ext3
- Mount the device and start using it !
Of course, when you have mounted the device, your data are readable to anyone who have access to the mounted directory.
Here is a quick picture about the impact of MySQL indexes misuse. At work, our developers made a new release of their search engine using MySQL fulltext indexes, unfortunately they didn’t implement it correctly. The impact was a huge load on all our database servers. To find the trouble, I had to redirect the SQL search flow to a specific server and check for the slow queries then reproduce it with EXPLAIN. Don’t need a long time to find that the search query did an invalid usage of the fulltext index and the "Match / Against" syntax. In fact, the fulltext index was a multiple column fulltext index, in such case you have to specify ALL the column present in your index, else the index won’t be used by MySQL...