Quick answer: connect to your VPS with SSH and run top (or htop) for CPU and memory, free -h for memory, df -h for disk space. If CPU or memory stay full all the time, upgrade your plan or reduce what your server runs.
Useful commands
toporhtop: which processes use the most CPU and memory.free -h: used and free memory.df -h: disk space on each drive.uptime: how busy the server has been over the last 1, 5 and 15 minutes.
How to read the numbers
- CPU always near 100%: a heavy script, heavy traffic or an attack. If it is normal load for you, you need a bigger plan.
- Memory always full: services such as databases and web servers may be slowed or stopped by the system.
- Disk almost full: delete old logs and backups or upgrade your storage.
- Bandwidth: your plan page lists the monthly bandwidth. Ask in a ticket if you think you are close to the limit.