There’s something magical about the term ‘self-healing’. Your body is self-healing (fortunately). You can also get self-healing bike parts, batteries, paint and car fenders – and now, self-healing virtual private server (VPS) hosting. If your web server goes down, normal service will be restored within as little as a few seconds according to provider claims. You continue to make a good impression on your visitors without constantly having to check up on your site or schedule regular, precautionary reboots by yourself.
What’s the Alternative?
In basic VPS hosting without self-healing, you may only discover your website is down when you receive an email from somebody else to ask you if there’s a problem. That’s embarrassing, to say the least. One solution is to manually and frequently check that your site is available. That still leaves you at risk during the time window between your last check and your next one. But do you really want to spend your time on this; and would you remember to do it anyway?
Cloud Self-Healing Designed-In
Cloud architectures are often designed so that servers operate together to share the computing load, and to provide resilience in case one of their number fails. This is the case in virtualization and cluster computing. Cloud providers with multiple, separate data centers can also organize their data storage and web hosting so that geographically distinct servers can back each other up. That way any disaster (power outage, flood or storm, for instance) that affects a server in one data center doesn’t necessarily have any impact on its companion server in another place.
Hypervisors for High Availability
The cloud provider can use a ‘hypervisor’ server, on which it loads individual virtual private servers like yours, with backups of your files on a separate storage area network (SAN). The hypervisor ensures that the different VPS’s continue to function properly. If the hypervisor itself has a problem, a new hypervisor is started on another system and uses your files that have been stored in safety on the storage area network. In these setups, your VPS can also be extended to high levels of volume and processing power. 27 GHz of processing power and 24 Gigabytes of RAM are the upper limits quoted by some providers.
Is It the Same as Fault Tolerant Computing?
Fault tolerant computing operates on the principle that there will never be any break in the service offered. Such fault tolerance can be expensive because of the resources and equipment needed to ensure this. On the other hand, for very sensitive environments such as financial trading or hospital emergency systems, it may be justified. In self-healing VPS hosting, there may be a short interval during which the replacement system starts up. For many business applications, the risk of having to restart a user session or losing the last few seconds’ of data is still acceptable – and the budget for self-healing VPS also a lot more affordable.