Unlike with shared hosting, there’s nobody monitoring the status of your unmanaged server. That responsibility is completely your own. If your server goes down at 4am, you may not know about it, potentially resulting in hours of downtime and lost revenue.

The solution is to use a third-party uptime monitoring service. These services will check your server regularly (at determined intervals) to ensure it is up. If your server goes down, the service will notify you, by email or SMS (depending on your uptime service plan).

It is possible to get both free and paid uptime monitoring service. Free services generally check your server less often only offer email for notifications. Paid services check your server more often and offer SMS notifications. If you’re running mission-critical, high-availability websites on your server, I would recommend using a paid service. Otherwise, if you’re just running your server more as a hobby, a free service will be sufficient enough.

By using an uptime monitoring service, you increase your chances of catching downtime sooner, and acting to correct it. The less downtime you have, the more money you can make with your websites. ;)

Two good uptime monitoring services are Pingdom and SiteUptime (the latter of which has a free plan).