How to fix error "system is deadlocked on memory" on Vultr VPS

The error "system is deadlocked on memory" "end Kernel panic - not syncing" usually indicates that the system has run out of available memory and processes are unable to allocate additional memory. This error comes from the VPS kernel, so it can be encountered in both Linux or Windows VPS operating systems. To resolve the issue on your Vultr VPS or any other service provider (Linode, Digitalocean ...) you can try the following steps:

Note: The first thing you need to do when you encounter this error is to quickly backup or snapshot VPS. Because the wrong operations at this time can cause you to lose the data in your VPS. 

Case 1 : Error on startup (can not start VPS)

1. Restart the server: If the issue persists, you can restart your Vultr VPS to clear the memory and resolve the deadlock.

2. Turn off the startup scripts with VPS (in VPS management) that you added (if exist)

3. Upgrading to a VPS droplet with more memory: If other solutions don't work, upgrading to a more configurable VPS plan might solve the situation. Upgrading VPS to a higher droplet at Vultr is easy, safe and does not affect your data or applications.

4. Contact Vultr for support: The last resort or if you are too worried about the current data in the VPS. Experts from Vultr will be able to help you fix the problem

Case 2: Error during operation (sometimes encounter)

1. Monitor resource usage: Use the 'top',' htop' command or "Task Manager' to monitor the resource usage of your system. Identify the processes that are consuming large amounts of memory and determine if they can be terminated or if their resource usage can be optimized.

2. Kill processes: If a specific process is consuming a large amount of memory and is not responding, terminate it.

3. Increase swap space(Linux): If your system does not have enough physical memory, you can increase the amount of swap space to temporarily address the issue.

4. Optimize application performance: If the issue recurs frequently, you may need to optimize the performance of your applications

It's important to monitor your system and its resource usage to identify and resolve issues before they become severe. Consider using a system monitoring tool to automatically alert you to any issues.