An IP you can transfer between servers
When you have a dedicated server with OVH, you can get failover IPs to host your projects, SSL certificates, etc. The failover IP can be switched from one server to another in a few seconds. This provides you with an uninterrupted hosting solution, and helps to overcome the headache of hardware failure, system overruns and all kinds of infrastructure problems. In order to take full advantage of the failover IP's potential, your hosting solutions must be configured with the failover IP (as opposed to the server's static IP).
So if you switch the failover IP from one server to another, you keep the entire configuration linked to that failover IP. You are responsible for copying your projects and configuration files from one server to the other. Since the configuration files are linked to the failover IP, and therefore the data and configurations remain the same, everything will keep working once you have switched the failover IP to the new server. You don't need to reconfigure all your projects with your new server's static IP.
Server change/Server upgrade
Your projects are hosted on dedicated server A (fixed IP A) and are configured with failover IP Z.
You may order a new server if server A isn't powerful enough to support your projects. Here it is described as server B, with fixed IP B.
You need to make copies of your projects and configuration files from server A to B. Then...
... you can change the routing of failover IP Z from server A to server B. As your projects' data and your configuration files are linked to the failover IP, they will continue to work on server B. You don't need to make any configuration changes (DNS, APACHE, SMTP, POP3, MySQL ...).
Working in a main server and a backup server
You have two servers: A and B. Server A is your main server, server B is your backup server.
Your projects are configured on failover IP Z, routed to server A. You can regularly copy your projects from server A to B.
If server A goes down, you can reroute the failover IP from server A to B. All your services will work on server B and you will have time to repair server A.
When you have repaired server A, you copy your data from server B to A. Then you reroute failover IP Z back to server A. All your services will once again work on server A.
The advantage of this solution is twofold:
- It enables you to back up the data on server A
- You can use server B of server A goes down
Hosting multiple projects
If you host multiple websites, you can host them on server A by using two failover IPs. Some of your websites will be hosted on failover IP Y and the rest on failover IP Z.
When server A doesn't have enough power to manage the wesites on both failover IPs: Y and Z, you can order another server (server B) and route failover IP Z to server B. Server A will then only host failover IP Y's websites, which will reduce the load and improve performance.