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Displaying posts with tag: ha (reset)
Picking a Deployment Method: Staging versus INI

Continuent Clustering is an extraordinarily flexible tool, with options at every layer of operation.

In this blog post, we will describe and discuss the two different methods for installing, updating and upgrading Continuent Clustering software.

When first designing a deployment, the question of installation methodology is answered by inspecting the environment and reviewing the customer’s specific needs.

Staging Deployment Methodology

All for One and One for All

Staging deployments were the original method of installing Continuent Clustering, and relied upon command-line tools to configure and install all cluster nodes at once from a central location called the staging server.

This staging server (which could be one of the cluster nodes) requires SSH access to …

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Cluster Performance Validation via Load Testing

Your database cluster contains your most business-critical data and therefore proper performance under load is critical to business health. If response time is slow, customers (and staff) get frustrated and the business suffers a slow-down.

If the database layer is unable to keep up with demand, all applications can and will suffer slow performance as a result.

To prevent this situation, use load tests to determine the throughput as objectively as possible.

In the sample load.pl script below, increase load by increasing the thread quantity.

You could also run this on a database with data in it without polluting the existing data since new test databases are created to match each node’s hostname for uniqueness.

Note: The examples in this blog post assume that a Connector is …

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Essential Cluster Monitoring Using Nagios and NRPE

In a previous post we went into detail about how to implement Tungsten-specific checks. In this post we will focus on the other standard Nagios checks that would help keep your cluster nodes healthy.

Your database cluster contains your most business-critical data. The slave nodes must be online, healthy and in sync with the master in order to be viable failover candidates.

This means keeping a close watch on the health of the databases nodes from many perspectives, from ensuring sufficient disk space to testing that replication traffic is flowing.

A robust monitoring setup is essential for cluster health and viability – if your replicator goes offline and you do not know about it, then that slave becomes effectively useless because it has stale data.

Nagios Checks The Power of Persistence

One …

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Global Multimaster Cluster Monitoring Using Nagios and NRPE

Your database cluster contains your most business-critical data. The slave nodes must be online, healthy and in sync with the master in order to be viable failover candidates.

This means keeping a close watch on the health of the databases nodes from many perspectives, from ensuring sufficient disk space to testing that replication traffic is flowing.

A robust monitoring setup is essential for cluster health and viability – if your replicator goes offline and you do not know about it, then that slave becomes effectively useless because it has stale data.

Big Brother is Watching You! The Power of Nagios

Even while you sleep, your servers are busy, and you simply cannot keep watch all the time. Now, more than ever, with global deployments, it is literally impossible to watch everything all the time.

Enter Nagios, you best big brother ever. As a long-time player in the monitoring market, Nagios has both …

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Worldwide Multimaster Cluster Administration Using Tungsten Dashboard

Continuent Clustering support true distributed multimaster clustering. In this topology, there are cross-site replicator services for each remote site. In a 3-site configuration, there are a total of 9 replication streams to manage.

Continuent Clustering also offers a graphical administration tool called the Tungsten Dashboard to help with your management burden. The GUI makes the deployment much easier to visualize and administer.

For our example, we will have a Composite Multimaster dataservice called global with three active, writable member clusters (one per site), east, west and north.

Dashboard Summary View

In the summary, collapsed view, the composite service and all member clusters are listed with associated information and controls. Note that the Type for the composite dataservice global is CompMM

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Multi-Cloud SaaS Applications: Speed + Availability = Success!

In this blog post, we talk about how to run applications across multiple clouds (i.e. AWS, Google Cloud, Microsoft Azure) using Continuent Clustering. You want your business-critical applications to withstand node, datacenter, availability-zone or regional failures. For SaaS apps, you also want to bring data close to your application users for faster response times and a better user experience. With cross-cloud capability, Continuent also helps avoid lock-in to any particular cloud provider.

The key to success for the database layer is to be available and respond rapidly.

From both a business and operational perspective, spreading the application across cloud environments from different vendors provides significant protection against vendor-specific outages and vendor lock-in. Running on multiple platforms provides greater …

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MySQL Router HA with Keepalived

After having explained how to achieve HA for MySQL Router for people who doesn’t want to install the MySQL Router on the application servers and after having illustrated how to use Pacemaker, this article explains how to setup HA for MySQL Router using keepalived.

Keepalived is very popular, maybe because it’s also very easy to use. We can of course use 2 or more servers. The principle is the same as on the previous articles, if the router dies, the virtual IP used by the application server(s) to connect to MySQL is sent to another machine where mysqlrouter is still running.

Let’s have a look at the configuration, in this case we use 2 machines, mysql1 and …

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MySQL Router HA with Pacemaker

This article will explain how to setup HA for MySQL Router as described in a previous article about where should the router stand.

For this setup, I will use Pacemaker (part of RedHat High Availability Add-on and available on RHEL, CentOS, Oracle Linux, …).

Of course we need a MySQL InnoDB Cluster but we won’t really use it for the HA setup of the MySQL Router.

Installing Pacemaker

The first step is to install pacemaker on all the machines we will use for our “MySQL Router Cluster”:

# yum install pacemaker pcs resource-agents

Now we need to start the pcsd service and enable it at boot (on all machines):

# systemctl start pcsd.service 
# systemctl enable pcsd.service

It’s time now to setup authentication, this operation is again …

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MySQL InnoDB Cluster: is the router a single point of failure ?

As you know, MySQL InnoDB Cluster is composed of 3 elements:

  • a group replication cluster of at least 3 servers
  • the MySQL Shell used to manage the cluster
  • the MySQL Router that send the traffic from the application server(s) to the cluster

When presenting the solution in conferences, one the main question is Where should I put the router ? and the answer is always the same: the best place to install the router is the application server !

The router is a very lightweight process that gets its configuration from the cluster’s metadata and doesn’t require a lot of resources or maintenance.

So the ideal setup is the following:

However for many (obscure?) reasons, sometimes people doesn’t want to have the MySQL …

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MySQL InnoDB Cluster : MySQL Shell and the AdminAPI

As promised, here is a post more detailed on how to create a MySQL InnoDB Cluster using MySQL Shell and the AdminAPI.

First of all, as a good practice is never enough repeated, whatever the version of MySQL you are using, please use the latest MySQL Shell ! So if you are using 5.7, please use MySQL Shell 8.0.11. See this compatibility matrix or this official one.

dba class

The AdminAPI can be accessed by the MySQL Shell via the dba object. The reference manual for this class is here. The Shell …

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