Now more than ever, organizations depend on their information technology and data storage systems everyday and cannot afford to have even an hour of downtime. These companies, however, must also ensure that their IT systems are consistently reliable and secure to protect their clients and so that the business remains in operation without interruptions. For example, hardware failures within a system typically cause major problems that could result in non-functioning systems for hours on end in addition to the risk of a loss of information and user dissatisfaction. This, of course, doesn’t have to happen and companies should actively work on not allowing it. One of the first and most effective measures to achieve protection against failures is the replication of your hardware and software components in a high-availability cluster.
What Is a High Availability Cluster and How Does It Work?
A high-availability cluster is a system made up of a set of two or more machines characterized by having the ability to maintain a series of shared services through constantly monitoring each other. In this way, the system guarantees uninterrupted operation of your applications via redundancies . Suppose that there is a hardware failure on one of the cluster machines. In this case, the high-availability software will automatically start the services on any of the other cluster machines. This is known as failover. When the failed machine recovers, the services are migrated back to it in a process known as failback. It allows us a high-availability of infrastructure of the services offered by the cluster to minimize the perception of the failure for the user. The capacity for automatic recovery of services on the failed server also guarantees a high application availability. This is the integrity of the information, considering that there is no loss of data or inconvenience for users, as they will not notice if a problem has occurred.
The Benefits of Implementing a High-Availability Cluster
There is a definite economic benefit to utilizing such redundancies in tech. Considering the costs associated with repairing a system failure, these clusters save time, effort, and money in the long-run. Users or employees who depend on the system will be affected as well and could lose productivity or work hours. This means a loss of income due to sales or services that have been stopped. In addition to fiscal repercussions, a system without working services brings with it a detriment of its reputation, bad publicity, mistrust of the employees, and (more importantly) dissatisfaction of the customers. Implementing a high-availability cluster not only increases availability as the name suggests, but also improves performance, scalability, fault tolerance, reduces costs, and strengthens servers and storage.
The Heartbeat Function
A high-availability cluster has two fundamental functions: 1. The intercommunication between all servers and continuously monitoring their status while detecting failures. 2. The management of resources offered by the cluster alongside having the ability to migrate these resources between the different physical servers in response to a failure.
The cluster software knows the availability of its servers at all times thanks to a technique known as the Heartbeat function. This function gets its name from the operation of each server that periodically informs of its existence by sending the rest a "life signal".
Common Settings for Cluster Servers
· Active/Active: In an active/active configuration, all of the servers in the cluster have the same resources and can access them independently of the other servers. If one of them fails, its resources are still accessible through the other servers in the cluster. · Active/Passive: This configuration consists of a main server that owns the cluster resources and others that are capable of accessing said resources, but only if the main one fails. The downside is that the servers do not provide any resources while they are on standby. This makes it a less efficient configuration because the systems take time to migrate the resources to the standby server. At Inudev, we design and maintain active/active cluster architectures to support enterprise-level applications of all kinds. We strive to keep updated with the latest and most optimal technologies to achieve this at cost-effective rates. If you want to take your application to the same level as Fortune 500 companies, you can schedule a call with our team that will provide you with all the advice and help you need. Contact us today to get started!