The server is very slow. What commands and what should be checked first? If you need to understand why the application does not write logs but the system is alive — where would you look?

If the server is slow, the first step is to check system resources:

• top or htop — check CPU load, memory, processes with the highest load.
• vmstat 1 — monitor memory usage, swap, IO.
• iostat -xz 1 — check disk activity and delays.
• free -m — memory and swap status.
• df -h — free disk space.

If the application does not write logs, but the system is alive:

• Check permissions and access to log files.
• Ensure that the disk is not full (df -h).
• Check if the log file is blocked (e.g., lsof | grep log_name).
• Check the logging configuration in the application.
• Check if the logging buffer is full (e.g., if buffering is used).
• Verify if the logging service has failed (e.g., systemctl status rsyslog or similar).

Thus, first look at system resources, then the state of files and logging configuration.