What restrictions and limits exist in the Linux operating system?

In Linux, there are several types of restrictions and limits that affect the operation of processes and the system as a whole:

• User resource limits (ulimit): These limit the use of memory, CPU time, the number of open files, etc. For example:

  • Maximum number of open files (nofile)
  • Maximum file size
  • Maximum number of processes

• Kernel restrictions: such as the maximum number of processes in the system, maximum message queue size, maximum number of network connections.

• File system restrictions: maximum file size, maximum number of files in a directory, maximum filename length.

• Network limits: maximum number of open sockets, data transfer speed restrictions.

You can check current limits with the command:

ulimit -a

For system limits — via /proc/sys/ or the sysctl command.

For example, to increase the maximum number of open files:

ulimit -n 65535

These restrictions are important for the stable operation of applications and to prevent resource exhaustion.