System High Availability and Hardware High Availability – What’s the Difference?

February 4, 2016 High Availability Blog Articles

High availability (HA) solutions are a world of their own. From the difference between logical and physical replication, to hot and cold failover sites and replication software – getting to know the technical side of HA can seem overwhelming. That’s why we’re here to break it down. Here you’ll learn about system high availability, hardware high availability, and the critical differences between each.


System High Availability Defined

System high availability is the type of HA most people are familiar with. This refers to the uptime of your company’s systems, typically achieved by replication software specific to your systems (like MIMIX for IBM i, or Zerto for virtual machines). This software replicates your data to one or multiple different sites. If your primary systems go offline, their availability will be maintained by “failing over” to your secondary target site (which is now equipped with a copy of your system data) so you can seamlessly pick up where you left off when systems went down.


Hardware High Availability Defined

Hardware high availability is the physical aspect of your HA solutions. This refers to having redundant systems, like a secondary or even tertiary site for restoration when your systems go offline. In order to keep your systems highly available, you must have a secondary set of fault tolerant hardware to pick up the slack. An example of this is RAID (Redundant Array of Independent Disks), which many companies use to store their data in multiple hard disks in case of a drive failure. Duplicate hardware is ideally housed off-premise, since many disasters that affect your primary production site could easily affect other on-premise systems as well.

Hardware HA is an important component of system HA, but is far from the whole picture. This is where the differences between system HA and hardware HA come into play.


The Difference Between System HA and Hardware HA

Companies often confuse hardware high availability (i.e. secure, redundant, fault-proof physical systems) with system high availability itself. While hardware HA is a critical component of system HA, it isn’t nearly enough to keep your systems available.

To achieve system HA, you need effective replication software, error detection and recovery mechanisms, and an established network, in addition to hardware redundancy. According to IBM’s Knowledge Center, hardware failures cause only a small percentage of unplanned downtime. Other causes, like environmental issues, human error, and application and operating system (OS) errors, are significantly more common (see this article for the full list of downtime threats). Simply having reliable hardware where you can restore your data is not enough to keep your systems secure and available.


For more information on how to keep your systems available, both from a hardware and software perspective, contact us today at 317-707-3941.


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