September 18, 2014 By Severalnines

Galera Cluster is a popular choice for achieving high availability using synchronous replication. Though if you are planning to run huge sites with many DB objects (tables), a few tweaks are necessary. 

Yes, you might have been successful in loading your 1000s of databases and 1000s of tables, but what happens if you have a node failure and Galera recovery fails?

In this blog post we will show you how to determine one common error related to the open_files_limit that MySQL imposes, and also to spot another potential pitfall.

Open_files_limit

If you are using wsrep_sst_method=xtrabackup or wsrep_sst_method=xtrabackup-v2 then you will find a log file in the data directory of the donor node. This log file is called innobackup.backup.log.

140912 19:10:15  innobackupex: Done. …

I recently encountered a situation in which after running Percona Toolkit’s pt-table-checksum on a customer system, 95% of the table on the MySQL master was different on the MySQL slave. Although this table was not a critical part of the infrastructure, from time to time, writes to the table from the master would break replication. Additionally, this table has about 6 million rows, and running pt-table-sync would take sometime. Rebuilding the slave from backup of the master would not be an easy option as well since the slave acts as an archive where it has a lot more data than the master.

So how did we solve it? With pt-online-schema-change and a NOOP ALTER.

pt-online-schema-change --alter 'ENGINE=INNODB' D=dbname,t=tblname

How is it …

September 17, 2014 By Severalnines

The Severalnines team is pleased to announce the release of ClusterControl 1.2.8. This release contains key new features along with performance improvements and bug fixes. We have outlined some of the key new features below. 

Highlights of ClusterControl 1.2.8 include:

• YUM/APT repositories for ClusterControl
• Deployment and scaling of single-node MySQL, MariaDB and MongoDB
• Alerts and incident tracking with PagerDuty 
• Unified Event Viewer
• New flexible alarms/email notification system
• Audit logging - Administrator activity tracking
• Global MySQL User Management
• New default dashboards for MySQL/MariaDB
• Puppet Module …

It's that time of the year again: yes, Oracle Open World is coming up and with that I'll be travelling to San Francisco. New for this year is that we are part of the main Open World event and therefore have our own MySQL Central. Here you will have the opportunity of meeting many of the engineers behind MySQL, discuss technical problems you have, and also learn some about how we look at the future of the MySQL ecosystem.

This year, me and Narayanan Venkateswaran will be presenting two sessions:

Elastic Scalability in MySQL Fabric with OpenStack (Thursday, Oct 2, 1:15 PM-2:00 PM in Moscone South, 252)

In this session you will see …

As the amount of data companies are interested in collecting grows, life becomes all the more difficult for IT staff at all levels within an organization. SAS Enterprise storage devices that were once considered giants are now being phased out in favor of SSD Arrays with features such as de-duplication, tape storage has pretty much been abandoned and the same goes without saying for database engines.

For many customers just storing data is not enough because of the CAPEX and OPEX that is involved, smarter ways of storing the same data are required and since databases generally account for the greatest portion of storage requirements across an application stack. Lately they are used not only for storing data but also for storing logs in many cases. IT managers, developers and system administrators very often turn to the DBA and pose the time old question “is there a way we can cut down on the space the database is taking …

As many of you know I'm actively developing libAttachSQL and am rapidly heading towards the first beta release.  For those who don't, libAttachSQL is a lightweight C connector for MySQL servers with a non-blocking API.  I am developing it as part of my day job for HP's Advanced Technology Group.  It was in-part born out of my frustration when dealing with MySQL and eventlet in Python back when I was working on various Openstack projects.  But there are many reasons why this is a good thing for C/C++ applications as well.

What you may not know is I will be giving a talk about libAttachSQL, the technology behind it and the decisions we made to get here at  …

With MySQL Enterprise Backup(MEB) 3.9.0 we had introduced full instance backup feature for cloning the MySQL server. Now with MEB 3.11.0 we have enhanced the feature by copying all the master-slave setup files like MySQL server binary logs(will be referred as 'binlogs'), binary log index files, relay logs of slave, relay log index files, master info of slave, slave info files. As part of full instance backup, copying of binlog files is default behavior MEB-3.11.0 onwards. DBA should be aware of the fact that current full instance backup is bigger than the backups with old MEB's.

As every event on MySQL production database goes as a entry to binlog files in particular format, binlog files could be huge. Backing of huge binlog and/or relaylog files should not impact the performance of MySQL server. Hence, all the binlog files, …

With the upcoming release of MySQL 5.7 I begin to see a problem which I think needs attention at least for 5.8 or whatever comes next. The GA release cycle is too long, being about 2 years and that means 3 years between upgrades in a production environment More people use MySQL and the data … Continue reading Making MySQL Better More Quickly

The early release of Fedora 20 disallowed installation of MySQL Workbench but the current version allows it. Almost like Tom Cruise’s Edge of Tomorrow without the drama. All you need to do is follow my earlier instructions for installing MySQL on Fedora 20. I’d check your kernel to know whether it’s supported. You can check that with this command:

<shell> uname -r

My Fedora is at the following version:

3.14.8-200.fc20.x86_64

Then, you can install MySQL Workbench with yum, like this:

<shell> sudo yum install mysql-workbench

It generates the following log file, and if you have Oracle 11g XE …

When you're testing out a new version of MySQL in a non-production environment there is a temptation to go wild and turn on all kinds of new features.  Especially if you're reading the changelogs or the manual and scanning through options.  You want to start with the most reasonable set of defaults, right?  Maybe you're even doing benchmarks to optimize performance using all the new bells and whistles.

Resist the temptation!  If your goal is to upgrade your production environment then what you really want is to isolate changes.  You want to preform the upgrade with as little to no impact as possible.  Then you can start turning on features or making changes one-by-one.

Why?  Anytime you're doing a major upgrade to something as fundamental as your core RDBMS, there are many ways things can go wrong.  Performance regressions & incompatible changes, client/server incompatibilities …