Proof-of-concept Tungsten support for MongoDB arrived last May, when I posted about our hackathon effort to replicate from MySQL to MongoDB.  That code then lay fallow for a few months while we worked on other things like parallel replication, but the period of idleness has ended.  Earlier this week I checked in fixes to Tungsten Replicator to add one-line installation support for MongoDB slaves.

MySQL to MongoDB replication will be officially supported in the Tungsten Replicator 2.0.5 build, which will be available in a few weeks.  However, you can try out MySQL to MongoDB …

Databases are the center of today’s web, enterprise and embedded applications, storing and protecting an organization’s most valuable assets and supporting business-critical applications. Just minutes of downtime can result in significant lost revenue and dissatisfied customers. Ensuring database highly availability is therefore a top priority for any organization.

The new MySQL Guide to High Availability solutions is designed to navigate users through the HA maze, discussing:

- The causes, effects and impacts of downtime;

- Methodologies to select the right HA solution;

- Different approaches to delivering highly available MySQL services;

- Operational best practices to meet Service Level Agreements (SLAs).

As discussed in the new Guide, selecting the high availability solution …

Databases are the center of today’s web, enterprise and embedded applications, storing and protecting an organization’s most valuable assets and supporting business-critical applications. Just minutes of downtime can result in significant lost revenue and dissatisfied customers. Ensuring database highly availability is therefore a top priority for any organization.

The new MySQL Guide to High Availability solutions is designed to navigate users through the HA maze, discussing:

- The causes, effects and impacts of downtime;

- Methodologies to select the right HA solution;

- Different approaches to delivering highly available MySQL services;

- Operational best practices to meet Service Level Agreements (SLAs).

As discussed in the new Guide, selecting the high availability solution …

When I talked about the usability improvements of Tungsten Replicator, I did not mention the procedure for upgrading. I was reminded about it by a question in the TR mailing list, and since the question was very relevant, I updated the Tungsten Cookbook with some quick upgrading instructions. A quick upgrading procedure is as important as the installer. Since we release software quite often, either because we have scheduled features to release or because of bug fixes, users want to apply a new release to an existing installation without much fuss. You can do the upgrade with a very quick and painless procedure. Let's suppose that you have installed one Tungsten Replicator cluster using this command:

#
# using tungsten-replicator 2.0.4
# …

I am looking for people who have a bunch of r/o slaves running, and who are using a load balancer to distribute queries across them.

The typical setup would be a PHP or Perl type of deployment with transient connections which end at the end of the page generation, and where a reconnect is being made at the next request serviced. The connect would go to the load balancer, which will forward it to any suitable database in the pool.

I am looking for people who are actually deploying this, and what strategies they have to cope with potential problems. I also would like to better understand what common problems are they needed to address.

Things I can imagine from the top of my head:

- Slave lag. Slave lag can happen on single boxes due to individual failures (battery on raid controller expires) or many boxes (ALTER TABLE logjams hierarchy). In the latter case boxes cannot be dropped from the …

MySQL built-in replication includes a concept called relay slave, which allows you to create hierarchical database clusters. You can do the same thing with Tungsten, and this can be done in more than one way. Let's start with two distinct clusters. We can follow the recipes in the Tungsten Cookbook to install a master / slave cluster in three separate hosts and a …

One lesson learned in more than two decades working in this industry is that most of the IT professionals are impatient, want to achieve results immediately, and, most importantly, they don't read documentation. Much as the average geek is happy to answer many requests with a dismissive RTFM, the same geeks are not as diligent when it comes to learning about new or updated technologies. For this reason, there is a kind of documentation that is very much appreciated by busy and impatient professionals: cookbooks. And I am not talking about food. Geeks are not known for being cooks (1) and they like fast food. I am talking about collection of technical recipes, short articles where a problem is briefly stated, and a direct solution is shown. Working with Tungsten Replicator, I am constantly amazed at all the things you can do with it, and at the same time, I am amazed at how so few …

Cross-site databases are the next challenge facing today's MySQL-based businesses. Continuent Tungsten enables multi-master with an innovative new architecture called System of Record that avoids data conflicts, ensures sites are ready for quick failover, and uses hardware resources efficiently.Watch this video from our 9/22/11 webcast to learn how Tungsten Enterprise enables System of Record

Intro
The open source Tungsten Replicator is very powerful. It's exciting to see how a flexible initial design allows to push the boundaries of replication with each new release. The recently published System of Record approach for multi-master databases does exactly this for multi-master databases.

Nevertheless, in today's database environments it is often not enough to move data, however well it is done, between the nodes of a single DBMS vendor like MySQL.  There is an entirely new set of challenges that appear when Oracle joins the Enterprise room.