How to Use the Command 'dstat' (with Examples)

dstat is a versatile tool used for generating comprehensive system resource statistics in real time. It serves as a powerful replacement for several existing tools and allows for easy monitoring of various system components such as CPU usage, memory load, disk activity, network statistics, and more. By combining these metrics, system administrators and enthusiasts can gain deeper insights into the system’s performance, helping to diagnose issues or plan for future resource needs.

Use Case 1: Display CPU, Disk, Net, Paging and System Statistics

Code:

dstat

Motivation:
The first use case for dstat is to provide a broad overview of your system’s performance. This command displays statistics on CPU utilization, disk operations, network data transfer, memory paging, and other system activities. This is beneficial when you need a holistic view of your system’s health.

Explanation:
When you execute dstat without any arguments, it defaults to showing you a range of essential system statistics. The default view includes:

• CPU: Usage statistics, helping you see how much processing power is being used.
• Disk: Information on I/O operations giving insight into read/write efficiency.
• Net: Network byte transfers (sent and received), indicating the volume of network traffic.
• Paging: Data on memory paging activities, which point to how the system handles processes that exceed physical memory.
• System: General system stats like interrupts and context switches, indicating system responsiveness and efficiency.

Example Output:

----total-cpu-usage---- --dsk/total- -net/total- --paging-- ---system--
usr sys idl wai hiq siq|_read _writ:_:recv _send: _in _out| int _csw 
 12  8  71   0   0   8|  30k   500k:   68k  120k: 200  150|1200   2500

Use Case 2: Display Statistics Every 5 Seconds and 4 Updates Only

Code:

dstat 5 4

Motivation:
In situations where you need a concise data set over a specific period, such as during a benchmark test or short debugging session, you can specify how often and how many times the stats should update. Limiting the data collection to a specific count can help prevent information overload and focus your analysis.

Explanation:

• The number 5 indicates the update interval in seconds. Thus, stats are refreshed every 5 seconds.
• The number 4 specifies that this refresh will occur only 4 times, resulting in a total monitoring window of 20 seconds.

Example Output:

----total-cpu-usage---- --dsk/total- -net/total- --paging-- ---system--
usr sys idl wai hiq siq|_read _writ:_:recv _send: _in _out| int _csw 
 10  7  75   0   0   8|  15k  2000k:   25k   60k:   0    0| 500  1200
 12  6  72   0   0  10|  50k 10000k:  180k  210k:   0    0|2000  2500
 15  4  81   0   0   0|  20k   300k:   10k   30k: 100  100| 300   700
  5 10  85   0   0   0|   5k    50k:    4k    8k:   0    0| 100   400

Use Case 3: Display CPU and Memory Statistics Only

Code:

dstat --cpu --mem

Motivation:
If your primary concern is about how well the CPU is performing and how memory is being utilized, you can request dstat to show only this subset of data. This simplified view is often used during performance tuning or when analyzing how individual applications affect system resources.

Explanation:

• --cpu instructs dstat to report statistics related to CPU usage, providing insights into how processing time is distributed.
• --mem specifies that the output should include memory statistics, such as available memory, usage indicators, and swap info.

Example Output:

---total-cpu-usage--- ----memory-usage----
usr sys idl wai hiq siq| used  buff  cach  free
  9   7  82   1   0   1|1532M  198M 2200M 1024M
 10   8  80   0   0   2|1540M  202M 2400M  990M

Use Case 4: List All Available dstat Plugins

Code:

dstat --list

Motivation:
dstat comes with a range of plugins that can extend its functionality to more specialized metrics, such as disk usage by partition, NFS stats, or additional network metrics. Listing these can be immensely useful to identify additional features and possibilities offered by dstat.

Explanation:

• --list commands dstat to present a list of all available plugins, providing a roadmap of optional and advanced statistics you can explore further.

Example Output:

battery, battery-remain, cpu, cpu-adv, cpu-use, mem, disk, net, page, sys, tcp, top-bio, top-io, top-cpu, top-latency, top-mem

Use Case 5: Display the Process Using the Most Memory and Most CPU

Code:

dstat --top-mem --top-cpu

Motivation:
Identifying resource-heavy applications or processes is crucial in system performance management, particularly when troubleshooting slow machine behavior or when suspecting memory leaks. This command focuses on pinpointing which processes are the prominent memory and CPU consumers, thus helping in efficient resource allocation or process optimizations.

Explanation:

• --top-mem shows stats on the process using the most memory, critical when ensuring optimal use of memory and no excessive consumption by a single process.
• --top-cpu lists the top CPU-consuming process, useful to detect programs that could potentially slow down system operations due to high processing demands.

Example Output:

----total-cpu-usage---- ----most-cpu-intensive---- ----most-memory-intensive----
usr sys idl wai hiq siq| proc   pid  cpu  |   proc   pid  mem
 20  10  60   0   0  10|python 1234  20%  | firefox 4321 1000M

Use Case 6: Display Battery Percentage and Remaining Battery Time

Code:

dstat --battery --battery-remain

Motivation:
For users on laptops or portable devices, being aware of battery status is essential. This command facilitates easy monitoring of both the current battery percentage and the estimated remaining runtime, promoting better power management and preventing unexpected shutdowns.

Explanation:

• --battery adds the battery percentage information to the output, showing how much charge is left.
• --battery-remain estimates and displays the time remaining until the battery is depleted, assisting users in gauging their available working time on unplugged power.

Example Output:

-----battery-----
Batt  Time
75%   120min

Conclusion

The dstat command stands out for its flexibility and comprehensiveness, making it a valuable tool for system administrators and users who need to monitor computer performance and troubleshoot performance issues efficiently. By leveraging different plugins and customization options, users can tailor dstat to meet specific requirements, from general system health monitoring to finer-grained metric tracking, making it an indispensable asset in the toolkit of modern IT professionals.