I have been very busy here in Malaysia this week. On thursday, I was asked to do a MySQL University session on MMM. The preparation was very stressful. There was no good wifi to be found until literally a few hours before the session (Big thank you to Gurdip at APIIT for providing a space and exceptional help!). On top of that, dimdim, the software used by MySQL for their sessions doesn’t seem to want to work on Linux (particularly the speaker part). I ended up using a laptop borrowed from APIIT with Vista and IE. Feels kind of counter-intuitive for a company in the FOSS business.

The session went very well and here is the resulting recording of the MMM talk on the mysqlforge page.

But that wasn’t the end of the MMM-promotion week: I happened to be allowed to present at the foss.my …

This Thursday (October 22nd, 13:00 UTC), Walter Heck (of Open Query) will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). Session slides (PDF).

The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more
information, see mysql-mmm.org.

For MySQL University sessions you point your browser …

This Thursday (October 22nd, 13:00 UTC), Walter Heck will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more information, see http://mysql-mmm.org/.

For MySQL University sessions, point your browser …

This Thursday (October 22nd, 13:00 UTC), Walter Heck will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more information, see http://mysql-mmm.org/.

For MySQL University sessions, point your browser …

This Thursday (October 22nd, 13:00 UTC), Walter Heck will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more information, see http://mysql-mmm.org/.

For MySQL University sessions, point your browser …

This is a “dogfood” type story (see below for explanation of the term)… Open Query has ideas on resilient architecture which it teaches (training) and recommends (consulting, support) to clients and the general public (blog, conferences, user group talks). Like many other businesses, when we first started we set up our infrastructure quickly and on the cheap, and it’s grown since. That’s how things grow naturally, and is as always a trade-off between keeping your business running and developing while also improving infrastructure (business processes and technical).

Quite a few months ago we also started investing (mostly time) in the technical infrastructure, and slowly moving the various systems across to new servers and splitting things up along the way. Around the same time, the main webserver frequently became unresponsive. I’ll spare you the details, we know what the problem was and it was predictable, but since it wasn’t …

We all knew that we are risking with MMM. Risking, and placing availability as a more important like consistency.  But non of us can risk loosing data forever but we show using it, regarding to our conversations think:  "I can fix my data later on, but I can’t turn back time and prevent the downtime. (Pascal Hofmann@xaprb.com)".

As I wrote before about staying online, now let me write about how to stay consistent.

We all know, mmm is not like a key of salvation, but its getting close to it . While MySQL doesn't support multi-master-slave environments from it's source code, we will sleep badly wondering on the safety of our precious databases.

But its not just about MMM, a few days ago we ran in to a well known InnoDB "feature". Its about the auto increment counter determination on restart. InnoDB try to count the next auto increment value on MySQL restart what can screw up things in the replication as in your …

I’ve been thinking recently about the failure scenarios of MySQL replication clusters, such as master-master pairs or master-master-with-slaves. There are a few tools that are designed to help manage failover and load balancing in such clusters, by moving virtual IP addresses around. The ones I’m familiar with don’t always do the right thing when an irregularity is detected. I’ve been debating what the best way to do replication clustering with automatic failover really is.

I’d like to hear your thoughts on the following question: what types of scenarios require what kind of response from such a tool?

I can think of a number of failures. Let me give just a few simple examples in a master-master pair:

Problem: Query overload on the writable master makes mysqld unresponsive

Do nothing. Moving the queries to another server will cause cascading failures.

Problem: The …

In this blog, I would like to mark myself as a power-user of MMM.  For more then 3 years now I'm engineering high-traffic websites and none of them was a small project. In the beginning I worked behind the livejasmin.com project (warning: NSFW!) which is an Alexa top100 site and now I'm working at ustream.tv which is in the top500 (so far). In this area, your greatest enemy is downtime. Thousands of users want to see your dynamic content by executing thousand of queries against your MySQL servers and what they don't have is the patience and they don't even tolerate critical security-upgrades. In both sites I mentioned above there is no point in time during the day at which less then 10k visitors are hitting the sites.  Now one question comes up: How can you do an upgrade on your MySQL servers or how can you alter a larger table?
So you have a new feature and that means another index on a table or you just want to upgrade your …

This is the first post on the brand spanking new MMM for MySQL Community Blog. Expect posts on new features for this great project. Expect user experiences.

So, your question is of course: what is MMM for MySQL and why haven't I heard of this before?

Well, MMM for MySQL is a project that strives to provide a HA Solution for MySQL, with automatic failover between multiple masters and slaves. If set up properly, you don't have to worry anymore over downtime for upgrading to a new version of MySQL, or a new version of your application (=> large alter tables, addition of indexes, etc.)

The project has recently reached it's version 2, which is a complete rewrite from scratch. We are now slowly seeing this being put into production, with some success stories making us happy already.

I won't make it too long here, but look forward to hear more from us!