Each virtual server has a fixed amount of RAM assigned to it, depending on the selected variant, i.e. in the range of 1 GB – 8 GB. This is the RAM that is seen by your operating system, which is installed in the virtual server.
The consumed RAM includes not only the memory consumed by running applications (WWW server, e-mail server and other services), but also the memory for running the operating system itself. This is the same as using RAM on a physical computer or server.
The allocated RAM cannot be exceeded in any way. The sum of the memory requirements of all applications and processes on your VPS can never exceed the allocated amount of RAM. When this happens, that is, processes and applications want to take more overall, the operating system usually starts to survive, randomly select some processes, and forcibly terminate them. As a result, the services on the server stop working. Also, the server is often congested and “freezes” overall.
Identifying and Solving the Problem
An example of solving a problem when using the Linux operating system.
Try logging in to the server via SSH. You may not be able to do this because Linux may have terminated SSH processes. You can access the server at any time via KVM, e.g. with the VeNCrypt program – you will find the necessary login data in the e-mail about setting up a VPS (attention, it differs from the data to SSH, you do not connect via the IP address of your VPS, but via a special domain name – stated in the establishment email).
You will usually find ‘Out Of Memory’ error messages on the monitor via KVM or in the server log.
How to solve the problem in general:
- If the server does not respond (i.e. it is frozen due to a lack of RAM), you must perform a hard reset.
- You need to find out what all the running processes are in Linux and how much RAM they are consuming. This can be done using the ps and top commands (see the manual pages or documentation for the Linux distribution used by you for details).
- If you do not want to upgrade to a higher variant of VPS, where more RAM is available, you must turn off some processes or services or limit them in some way.
- In any case, it is possible to switch to a higher variant and thus have more RAM available – increasing parameters.
Definitely do not try to solve the problem of a lack of RAM by adding a swap – usually the opposite effect will occur, the running of the server and services on it will usually not improve, but on the contrary will deteriorate rapidly. This is because accessing data in disk swap is significantly slower than working with data in RAM – your server will start to freeze more often.
The Minimum and Recommended RAM Sizes
A basic installation of Linux requires 512 MB of RAM, but with other services running, its consumption increases. If you want to run a WWW server and an e-mail server on the server, it is better to have 1 GB available, which we offer as a minimum configuration. Of course, it also depends on the load of your server – with each increase in traffic comes more RAM consumption.
We only offer the pre-installed Debian ISP package with a RAM of 1 GB or more. With 512 MB of memory, you would soon run out of RAM due to the number of applications and services installed.
We supply the Windows operating system in a minimum configuration with 1 GB of RAM. With less, the server would be unusable.
By increasing RAM, you can also generally achieve significantly higher performance of the entire server and all services, because the more RAM the operating system has available, the more it can use to cache various things and the less forced it is to access data on the hard disk (a so-called file cache).