Troubleshooting

Health & Performance

CPU

# cat /proc/cpuinfo

1. lscpu
2. sensors <- necesita "apt install lm-sensors"
3. htop
4. mpstat -P ALL 1
5. ps aux --sort=-%cpu | head -10 <- cei mai mari 10 consumatori de CPU

RAM

# free -h

1. awk '$3=="kB"{$2=$2/1024;$3="MB"} 1' /proc/meminfo | column -t <- conversie in MB
2. awk '$3=="kB"{$2=$2/1024**2;$3="GB";} 1' /proc/meminfo | column -t <- conversie in GB
3. ps aux --sort=-%mem | head -n 10 <- cei mai mari 10 consumatori de RAM

Disk

1. df -h
2. df -hi <- arata si inode
3. du -hx --max-depth=1 /etc/ | sort -h <- afiseaza toate directoarele si fisierele din /etc/ sortate in ordinea crescatoare a dimensiunii
4. du -ah / | sort -rh | head -10 <- arata cele mai mari 10 fisiere sau directoare
5. watch -d -n 60 'df -H /dev/sd[a-z][0-9] | sort -r -k 5 -i' <- watch pe "df -h" pentru toate disk-urile montate
6. lsblk -f
7. fdisk -l

Status

1. vmstat 1
2. uptime

Services & Logs

1. systemctl restart <serviciu>
2. systemctl start <serviciu>
3. systemctl stop <serviciu>

Journal

1. journalctl -xb <- logurile de la ultimul boot
2. journalctl --since "2026-12-01 10:00" <- loguri incepand cu "2026-12-01 10:00"
3. journalctl -u <serviciu> -f <- loguri specifice unui serviciu
4. journalctl -xe <- erori recente din journal

Kernel

1. dmesg -T
2. dmesg --level=err <- filtrare dupa erori

Network

1. netstat -tulnp
2. ss -tulnp <- afiseaza porturile si socket cu LISTEN activ
3. ping -c 3 google.com <- ping catre IP/Domeniu
4. traceroute google.co traseul pachetelor catre IP/Domeniu
5. lsof -i :443 <- afiseaza porturile si conexiunile (exemplu pt 443)
6. tcpdump -i ens18 <- captura de pachete pe din interfata ens18

Procese

1. ps aux
2. ps aux | grep <serviciu>
3. ps axo stat,ppid,pid,comm | grep -w defunct <- identifica procese zombie
4. ps -eo pid,ppid,state,cmd | grep " D " <- afiseaza procese aflate in "Uninterruptible Sleep"