Performance Monitoring

htop

Interactive process viewer — the standard replacement for top.

apt install htop
htop

Key bindings: F6 sort, F9 kill, F10 quit, / search, u filter by user.

dstat

Versatile resource statistics tool.

apt install dstat

# All stats with timestamp
dstat -cdngy --time

# CPU, disk, network, memory
dstat -c -d -n -m

collectl

Collects performance data similar to sar but more flexible.

apt install collectl

# Real-time display
collectl

# Record to file
collectl -f /var/log/collectl/

nmon

Nigel’s Performance Monitor — comprehensive system stats in one screen.

apt install nmon
nmon

Press: c CPU, m memory, n network, d disk, k kernel, q quit.

saidar

Simple curses-based system information tool.

apt install saidar
saidar -c    # with colors

sar — System Activity Reporter

Part of the sysstat package.

apt install sysstat

# CPU usage (10 intervals of 2 seconds)
sar -u 2 10

# Memory
sar -r 2 10

# Disk I/O
sar -d 2 10

# Network
sar -n DEV 2 10

# View historical data
sar -u -f /var/log/sysstat/sa$(date +%d)

glances

Modern, all-in-one system monitor with web interface option.

pip install glances
# or
apt install glances

# Terminal mode
glances

# Web server mode (access via http://host:61208)
glances -w

atop

Advanced system and process monitor — records history for later analysis.

apt install atop

# Interactive
atop

# Record to file every 10 minutes
atop -w /var/log/atop/atop_$(date +%Y%m%d) 600

# Replay recorded session
atop -r /var/log/atop/atop_20250101