As part of a recent engagement, I described the relative products to manage a MySQL pair (i.e. an Active/Passive MySQL masters configuration). This included the steps to undertake a controlled failover for supporting software maintenance using manual procedures. The upcoming Effective MySQL: Replication Techniques in Depth book details each step and all conditions to review over a dozen pages. While the steps are straightforward and generally well known, scripting this for your environment takes a certain amount of work to ensure your information is correct, and application connectivity loss is kept to a minimum.

In Continuent Tungsten (which I have just been reviewing these past few weeks), I achieved the same result with a single command.

$ echo "switch" | /opt/continuent/tungsten/tungsten-manager/bin/cctrl

In addition to all the …

High availability is about more than just making sure that applications can get to your data, even if there is a failure:

How about when you are upgrading your database schema What if you need to add memory to a database server or reconfigure/restart MySQL If your apps want to read data from a MySQL slave, how can you be sure they are not reading stale data without re-coding your apps What

Oracle is the most powerful database system in the world. However, Oracle's expensive and complex replication makes it difficult to build highly available applications or move data in real-time to data warehouses and popular databases like MySQL.

In this webinar you will learn how Continuent Tungsten solves problems with Oracle replication at a fraction of the cost of other solutions and

Suddenly your application starts throwing "error 157" and performance degrades or is non-existing. It is easy to panic then and try all sorts of actions to get past the problem. We have seen several users doing:

• rolling restart
• stop cluster / start cluster

because they also see this in the error logs:

120828 13:15:11 [Warning] NDB: Could not acquire global schema lock (4009)Cluster Failure

That is not a really a nice error message. To begin with, it is a WARNING when something is obviously wrong. IMHO, it should be CRITICAL. Secondly, the message ‘Cluster Failure’ is misleading.  The cluster may not really have failed, so there is no point trying to restart it before we know more.

So what does error 157 mean and what can we do about it?

By using perror we can get a hint what it means:

$ …

MySQL data rules the cloud, but recent experience shows us that there's no substitute for maintaining copies of data, across availability zones, when it comes to Amazon Web Services (AWS) data resilience.

In this video (recording of our 8/23/12 webcast), we survey technologies for maintaining real-time copies of your data and the pros & cons of each. We conclude with a live demonstration of a

MySQL 5.6 Replication - Global Transaction IDs

On Wednesday (16th May 2012), Mat Keep and I presented on the new replication features that are previewed as part of the latest MySQL 5.6 Development Release.

The replay for that webinar (together with the chart deck) is now available from here.

In addition, there were a huge number of great questions raised and we had a couple of  key engineers answering them on-line – view the Q&A transcript here.

A reminder of the topics covered in the webinar…

MySQL 5.6 delivers new replication capabilities which we will discuss in the …

When preparing for the the IOUG Collaborate 12 deep dive on deploying Oracle Databases for high Availability, I wanted to provide some feedback on what hardware components are failing most frequently and which ones are less frequently. I believe I have reasonably good idea about that but I thought that providing some more objective data would be better. I couldn’t find and results of a more scientific research so I decided to organize a poll. This blog post shows the results and I promised to share it with several groups.

The results are also in the presentation material but it might be hidden deep into 100+ slides so here is the dedicated blog with some comments on the …

MySQL 5.6 Replication - Global Transaction IDs

On Wednesday (16th May 2012), Mat Keep and I will be presenting the new replication features that are previewed as part of the latest MySQL 5.6 Development Release. If you’d like to attend then register here.

MySQL 5.6 delivers new replication capabilities which we will discuss in the webinar:

• High performance with Multi-Threaded Slaves and Optimized Row Based Replication
• High availability with Global Transaction Identifiers, Failover Utilities and Crash Safe Slaves & Binlog
• Data integrity with Replication Event Checksums
• Dev/Ops agility with new Replication Utilities, Time Delayed Replication and more

High availability is about more than just making sure that applications can get to your data, even if there is a failure:

How about when you are upgrading your database schema What if you need to add memory to a database server or reconfigure/restart MySQL If your apps want to read data from a MySQL slave, how can you be sure they are not reading stale data without re-coding your apps What

The Helsinki MySQL User Group will meet at the usual place on May 29th. Click here for details and to RSVP. Linas Varbalas will talk about Tungsten and maybe dare a live demo!

Linas is in town for the OUGF Harmony conference 2012. The conference might of course be of some interest to user group members too. Due to the conference we also have other famous MySQLrs in town, Sheeri Kabral of OurSQLcast fame has also confirmed she will attend the user group (and maybe have OurSQLcast CD's with her?)