When your site needs more power than a single server, or you want to insure yourself against hardware failure, Bytemark's powerful multi-site clustering facilities are the answer.
A private network - the first step
If you have one or more dedicated or premium dedicated servers with Bytemark, we can install them (or move them onto) a private network with its own range of IP addresses for only £10/month.
This is the first step towards a cluster, and means that database connections, and other sensitive data can be more confidently transferred between your machines. It also means you can reassign IP addresses between your servers without us being involved.
Planning a real cluster
It's counter-intuitive, but the more machines you have performing different functions for the same site, the less reliable your site becomes overall, as only one machine failure will stop it from working. That is more likely the more servers you have.
So we always advise our cost-conscious customers to upgrade a single server as far as they can (and with our premium servers that's a long way) before they think about a cluster.
Once you've taken that step, and you want to ensure that a server failure does not bring your site down, your whole setup must meet the following criteria:
- it must have more than one server;
- each server must have exactly the same setup;
- servers must be replicating their data between themselves;
- the application running on the servers must not rely on local data;
- the servers must be behind replicated load balancers (see below).
If you need help planning your load balanced setup, you might be interested in our managed service, where we can take the setup headaches away, leaving your developers to concentrate on their software. We're also happy to work with you if you just want the network setup, and you can manage the details yourself.
Once you have your private network, we can hand some of your IP addresses to our load balancers. They will answer connections, and send them on to your real servers, thus spreading the load between them.
The load balancers are configured to notice when your servers malfunction, and stop sending connections to them, thus ensuring continuous service in the event of a single server failure.
Load balancing is priced at £5 per service per per month, and requires a private network.
For customers ordering multiple servers, where we think it will make a real difference to their uptime, we can offer dual site redundancy in our second Manchester data centre, at no extra charge.