Linux Admin Zone

Sometimes in large deployments, there are cases when MySQL server, setup by you long time back which has been in use by multiple teams in your organization, needs some change or update or intrupption in its service and you are in need to know how many clients are there which connects to this server.

One way to know is to check user table in ‘mysql’ database, you might have created individual users/databases for your clients/users. But over the time, unless taking care seriously, we tend to forget the exactly how many users/scripts/machines are there making connections. May be you have used same read-only user in various scripts scattered over many machines which you’ve created just for a single client.

MySQL Cluster is used to provide high-availability, high-redundancy for the distributed computing environment. You might know that beginning with MySQL 5.1.24, support for the NDBCLUSTER storage engine was removed from the standard MySQL server binaries built by MySQL. Therefore, here I’m using MySQL Cluster edition instead of MySQL Community edition. I’m using 3 servers (1 Management and 2 data) to setup cluster in CentOS 5.4 Linux box. The steps mentioned here can be used for quickly deploying a cluster and worked out for me but no guarantee that this will work for you, So its always advisable to go through official MySQL guide as well for production environment. In case you are also riding on cloud computing wave, I’ve already blogged way to setup MySQL cluster in Amazon EC2 environment.