Dedicated Servers are designed to be on all of the time, hence the word “dedicated”. A desktop computer that serves as a part-time server is not sufficient. Even a server in a data center that gets shut off for any longer than a few minutes is probably not really a dedicated server. To wear that badge, the server must stay on 24 hours a day and 7 days a week.
Rebooting any computer causes a temporary interruption in whatever activity the computer normally does. Rebooting a dedicated server can interrupt service for a lot of people, especially if the server hosts popular websites. When possible, the system administrator should keep reboots to an absolute minimum.
On a Linux server, this is very realistic. Reboots in Linux are very rarely needed. Here are a few example scenarios, along with an alternative to rebooting.
1. Websites inaccessible. If you cannot reach websites but can still log in to the server via SSH, you may just need to restart your web server. With Apache, a simple “service httpd restart” may do the trick.
2. Slow, unresponsiveness. There are many possible causes for a slow server, some of which may involve attackers. Find the cause of the problem and neutralize it, but there is no need to reboot.
3. Configuration changes. Almost all configuration changes can be applied without having to restart the entire operating system.
4. Updates. Most updates do not affect the kernel and, therefore, do not need a reboot. Only a kernel upgrade requires a reboot.
As you can see, reboots are very rare and only needed when the server is completely unreachable, even through SSH, or when you perform kernel updates.