There are three ways to decide if your server is too old:

1. It stops being powerful enough to do the job it was intended for.
2. The operating system installed on it is no longer supported by its supplier.
3. The hardware becomes unreliable.

To elaborate a little on these points:

It stops being powerful enough to do the job it was intended for.

This, as you can imagine, is a little bit subjective. If the server has been specified correctly, it should not be a problem for at least as long as the hardware is reliable, and the software is supported. However, there are a large number of factors that can ultimately affect the server’s performance which may not be known when it is first being specified.

The main one would be user growth. If, for example, a server was designed based on having only 4 people working on it concurrently, but the business grows at a much faster speed than expected, and you end up with 20 people trying to use it at the same time, you are going to run into performance issues.

The good news is that if the server has been designed properly then you should be able to add more storage and additional memory to help mitigate the issues.

If the initial configuration has been done properly (and assuming there are no unexpected levels of growth), then a server should last between 3 and 6 years depending on the other two factors outlined above.

The operating system installed on it is no longer supported by its supplier.

This is really quite simple. Server operating systems from the major software suppliers (Microsoft and Linux/Unix) will have an end of support date confirmed almost from the launch of the software.

Once an operating system goes past end of life support, you will not receive any more security or feature updates. This puts you at risk from malicious software and viruses – something you do not want to happen to your server.

In the case of Microsoft Windows Server operating systems, there are 5 years of mainstream support and 5 years of extended support.  For Linux this varies by supplier, but is generally 5 years.

This means that realistically, even if you install the operating system on the day of launch, you would not want to run it for any more than 5 years for Linux and 10 years for Windows.

The hardware becomes unreliable.

This third point is the most difficult to answer as it depends on a very large number of factors. If your server has been built by a reputable company such as Dell or HP then the build quality and component quality tends to be much better.  If you are building your own, then while you might buy the best components it can be very difficult to make sure everything works together properly and that things like temperature management is handled properly.  It also means that replacement parts are not always going to be as easily available.

If you are buying direct from one of the major companies, we recommend you always buy the longest hardware support option available, which tends to be 5 years.

In conclusion, if you server is over 5 years old, it almost certainly needs to be replaced with both new hardware and a more up to date version of the operating system.

Ideally you would start to plan for your upgrade between 6 and 9 months before that age, to allow time to configure the replacement server and migrate your data and users from the old machine to the new one.