Using dstat

Using dstat

dstat (now often replaced by dool on newer Ubuntu) combines CPU, disk, network, and memory statistics in a single colorized output. It is the most readable real-time overview tool, designed as a replacement for vmstat + iostat + netstat in one view. When you want to watch all system resources simultaneously with one command, dstat is the right tool.

Why dstat?

Without dstat — need multiple terminal windows:
  Terminal 1: vmstat 1          (CPU + memory + swap)
  Terminal 2: iostat -xz 1      (disk I/O)
  Terminal 3: ifstat -i eth0 1  (network bandwidth)

With dstat — everything in one view:
  dstat -cdngm 1
  Shows: CPU, disk, network, paging, memory — all in one line per second

Basic dstat usage

# Install dstat:
sudo apt install -y dstat

# Default view (CPU + disk + net + paging + system):
dstat

# 1-second intervals with color:
dstat 1

dstat default output

----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system--
usr sys idl wai  hiq siq| read  writ| recv  send|  in   out | int   csw
 34   8  55   2    0   0| 892k  445k| 234k  123k|   0     0 | 1.2k 4.5k
 45  12  38   4    0   0| 912k  892k| 345k  234k|   0     4 | 1.8k 5.2k

Custom column combinations

# Select specific metrics with flags:
dstat -c          # CPU only
dstat -d          # Disk I/O only
dstat -n          # Network only
dstat -m          # Memory usage
dstat -g          # Paging/swap activity

# Common combinations:
dstat -cdnm 1     # CPU + disk + net + memory
dstat --top-cpu   # Add column showing highest CPU process
dstat --top-io    # Add column showing highest I/O process

# Full overview with process info:
dstat -cdnmg --top-cpu --top-io 1

dstat with --top-cpu and --top-io

----cpu---- -dsk-- -net-- -mem-- --top-cpu-- --top-io--
usr sys idl|read writ|recv send|used free|cpu  process|process
 45  12  38| 892k 445k| 234k 123k| 3.2G  4.1G|34.5 mysqld | mysqld
 50   8  38| 1.2M 892k| 312k 145k| 3.3G  4.0G|42.1 mysqld | mysqld

# dstat also supports output to CSV for logging:
dstat --output /var/log/dstat.csv -cdnm 60 &    # Background, 60-second intervals

Conclusion

dstat is the best single-screen tool for real-time system performance overview. The --top-cpu and --top-io plugins make it particularly useful for quickly identifying which process is driving CPU or disk activity without needing to run top or iotop separately. On Ubuntu 22.04+, dstat may be replaced by dool (its Python 3 rewrite) — the syntax is identical.