...
Monitoring CPU and memory usage helps in identifying performance bottlenecks.
htop is an interactive system monitor process viewer and process manager. It is designed as an alternative to the Unix program top. It shows a frequently updated list of the processes running on a computer, normally ordered by the amount of CPU usage.
| Code Block | ||||
|---|---|---|---|---|
| ||||
htop |
2. vmstat -s Provides a detailed breakdown of memory usage and other related metrics since the last system boot.
| Code Block | ||||
|---|---|---|---|---|
| ||||
vmstat -s
980492 K total memory
480208 K used memory
132040 K active memory
582364 K inactive memory
67924 K free memory
21724 K buffer memory
410636 K swap cache
0 K total swap
0 K used swap
0 K free swap |
3. free -h Displays memory usage in "human-readable" format
...
Keeping track of disk usage and health is crucial for preventing data loss and ensuring efficient storage management.
1. df -h # Shows disk space usage in "human-readable" format
| Code Block | ||||
|---|---|---|---|---|
| ||||
df -h Filesystem Size Used Avail Use% Mounted on udev 3.8G 0 3.8G 0% /dev tmpfs 783M 1.7M 781M 1% /run /dev/sda2 233G 25G 197G 12% / tmpfs 3.9G 39M 3.8G 1% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 783M 80K 783M 1% /run/user/1000 |
2. du -sh /path/to/directory Displays the size of a specific directory.
| Code Block | ||||||
|---|---|---|---|---|---|---|
| ||||||
du -sh /path/to/directory 1.1G /path/to/director iostat # Reports CPU and I/O statistics. |
3. fdisk -l # List all partitions
...
Managing processes and services is essential for maintaining system stability.
ps aux # Lists all running processes
| Code Block | ||||||
|---|---|---|---|---|---|---|
| ||||||
ps aux # Lists all running processes. USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0.0 0.0 168800 10944 ? Ss Jun12 0:02 /sbin/init systemctl status service_name # Checks the status of a serviceroot 2 0.0 0.0 0 0 ? S Jun12 0:00 [kthreadd] root 3 0.0 0.0 0 0 ? I< Jun12 0:00 [rcu_gp] root 4 0.0 0.0 0 0 ? I< Jun12 0:00 [rcu_par_gp] ... journalctl -u service_name # Views logs for a specific service. kill -9 process_id # Forces termination of a process. nice and renice # Adjusts process priority. |
systemctl status service_name # Checks the status of a service
| Code Block | ||||||
|---|---|---|---|---|---|---|
| ||||||
systemctl status apache2
● apache2.service - The Apache HTTP Server
Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2024-05-29 16:06:04 UTC; 2 weeks 5 days ago
Docs: https://httpd.apache.org/docs/2.4/
Process: 1000205 ExecReload=/usr/sbin/apachectl graceful (code=exited, status=0/SUCCESS)
Main PID: 40385 (apache2)
Tasks: 55 (limit: 1013)
Memory: 8.8M
CPU: 1min 55.654s
CGroup: /system.slice/apache2.service
├─ 40385 /usr/sbin/apache2 -k start
├─1000209 /usr/sbin/apache2 -k start
└─1000210 /usr/sbin/apache2 -k start |
ps aux # Lists all running processes
| Code Block | ||||||
|---|---|---|---|---|---|---|
| ||||||
ps aux # Lists all running processes.
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 168800 10944 ? Ss Jun12 0:02 /sbin/init
root 2 0.0 0.0 0 0 ? S Jun12 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? I< Jun12 0:00 [rcu_gp]
root 4 0.0 0.0 0 0 ? I< Jun12 0:00 [rcu_par_gp]
...
|
kill -9 process_id(PID) # Forces termination of a process.
| Div | ||
|---|---|---|
| ||
Logs and Monitoring |
...