In the last 10 years I have worked a lot with replication systems, and I have developed a keen interest in the topic of multiple masters in a single cluster. My interest has a two distinct origins:

• On one hand, I have interacted countless times with users who want to use a replication system as a drop-in replacement for a single server. In many cases, especially when users are dealing with applications that are not much flexible or modular, this means that the replication system must have several points of data entry, and such points must work independently and in symbiosis with the rest of the nodes.
• On the other hand, I am a technology lover (look it up in the dictionary: it is spelled geek), and as such I get my curiosity stirred whenever I discover a new possibility of implementing multi-master systems.

The double nature of this professional curiosity makes me sometimes forget that the …

MySQL and Scaling-up (using more powerful hardware) was always a hot topic. Originally MySQL did not scale well with multiple CPUs; there were times when InnoDB performed poorer with more  CPU cores than with less CPU cores. MySQL 5.6 can scale significantly better; however there is still 1 big limitation: 1 SQL query will eventually use only 1 CPU core (no parallelism). Here is what I mean by that: let’s say we have a complex query which will need to scan million of rows and may need to create a temporary table; in this case MySQL will not be able to scan the table in multiple threads (even with partitioning) so the single query will not be faster on the more powerful server. On the contrary, a server with more slower CPUs will show worse performance than the server with less (but faster) CPUs.

To address this issue we can use a parallel …

I’m writing this blog as 2013 draws to an end. Like many people do at this time of year, I want to take a moment to reflect on the year gone by and to plan for the year ahead. For some, this might be a time to think about a new job or to hire a new team member/employee.

As I reflect, one of the questions that I have been asked repeatedly throughout the year is, “When looking or hiring a MySQL DBA, what are the best questions to ask during an interview?” Over my professional career, I have been on both sides of this question as a potential candidate and as an interviewer.

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This week we discuss administering Percona Replication Manager. Ear Candy is about repository packages from MariaDB and Oracle, and At the Movies presents a Riak engineer talking about "convergent replicated data types" - data structures that tolerate eventual consistency.

Events
DB Hangops - every other Wednesay at noon Pacific time

FOSDEM 2014 - Sat February 1 - Sun February 2 in Brussels, Belgium.
Upcoming MySQL events

The call for papers for OSCon 2014 is open until Thursday, January 30th

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We are pleased to announce that MySQL Enterprise Monitor 3.0.5 is now available for download on the My Oracle Support (MOS) web site. It will also be available via the Oracle Software Delivery Cloud with the January update in about 1 week. This is a maintenance release that fixes a number of bugs. You can find more information on the contents of this release in the change log.

You will find binaries for the new release on My Oracle Support. Choose the "Patches & Updates" tab, and then use the "Product or Family (Advanced Search)" feature.

You will also find the binaries on the Oracle Software Delivery Cloud in approximately 1 week. Choose "MySQL Database" as the Product Pack and you will find the Enterprise Monitor along …

January 6, 2014 By Severalnines

MySQL Cluster is a popular backend for FreeRADIUS, as it provides a scalable backend to store user and accounting data. However, there are situations when the backend database becomes a centralized datastore for additional applications and services, and needs to take a more general-purpose role. NDB usually works very well for FreeRADIUS data, but for wider use cases and reporting type applications, InnoDB can be a better storage engine. For users who need to keep their data in InnoDB and still benefit from a highly available clustered datastore, Galera Cluster can be an appropriate alternative.

In this post, we will show you how to deploy FreeRadius both with MySQL Cluster and Galera Cluster to store user and accounting data. All servers are running CentOS 6.4 64bit.

FreeRadius Deployment with Galera

We will deploy a two-node FreeRadius cluster …

In Part 1 we started our study of Amazon Services and looked at Amazon EC2. In this part, we will look at other Amazon services like EMR, DynamoDB and RDS.

1. 1.      Amazon Elastic Map Reduce

Amazon EMR is a web service which makes cloud computing very easy. Amazon’s EMR cluster comes preconfigured with Hadoop, which as mentioned earlier is a data processing and storage framework. This preconfiguration makes it very easy to start analysing your data in no time. Amazon EMR has applications in machine learning, financial analysis, bioinformatics etc.

Just like EC2, you can launch any number of EMR instances as you need and you will only be charged for the computing power you have used. EMR is preconfigured …

MySQL Cluster is a technology providing shared-nothing clustering and auto-sharding for the MySQL database management system. It is designed to provide high availability and high throughput with low latency, while allowing for near linear scalability.

To learn more about MySQL Cluster, take the 3-day MySQL Cluster training course. Below is a selection of events already on the schedule for this course.

Sometimes there is a need for keeping large amounts of old, rarely used data without investing too much on expensive storage. Very often such data doesn’t need to be updated anymore, or the intent is to leave it untouched. I sometimes wonder what I should really suggest to our Support customers.

For this purpose, the archive storage engine, added in MySQL 4.1.3, seems perfect as it provides excellent compression and the only DML statement it does allow is INSERT. However, does it really work as you would expect?

First of all, it has some serious limitations. Apart from lack of support for DELETE, REPLACE and UPDATE statements (which may be acceptable for some needs), another one is that it does not allow you to have indexes, although you can have an auto_increment column being either a unique or non-unique index. So usually …

#DBHangOps 01/08/14 -- Sharding (part 2), Load balancing, and more!

Thanks for watching. You can catch the recording below!

Hello everybody!

Join in #DBHangOps this Wednesday, January, 08, 2014 at 12:00pm pacific (19:00 GMT), to participate in the discussion about:

• Sharding (part 2)

  • Horizontal vs. Vertical -- When do you choose to do one? How do you plan for this?

• Load balancing and MySQL -- What do you use for load balancing (hardware or software)?

  • How does this influence your application configuration?
  • Best practices for load balancers and MySQL

Be sure to check out the #DBHangOps twitter search, the …