Load testing with Siege

We previously installed Siege, and we are now ready to play with it a bit. Consider the following command:

siege -c5 -d5 -t10S http://localhost:8000/list

-cNUM is the number of concurrent users. In the example it is set to 5, and is 10 by default if not set.

-dNUM is any random number of seconds for the time delay (between 1 and NUM) that each “user” will sleep for between requests.

-tNUMm is the duration of the test. m indicates the time unit and can be S for seconds, M for minutes or H for hoursĀ 

In the above example, we are putting the server under siege with 3 concurrent users sending requests for 10 seconds, and being idle for 1 – 5 seconds between each request.

Below is the result when running the test against a Node.js app which does some queries to MongoDB to list some items. The templating engine used here is Jade with the caching mechanism enabled.

Lifting the server siege...
Transactions: 18 hits //number of server hits
Availability: 100.00 % //server was fully available
Elapsed time: 9.63 secs //duration of test
Data transferred: 0.12 MB //data transferred to every siege simulated user and includes header information
Response time: 1.46 secs //average time taken to respond to each user's requests
Transaction rate: 1.87 trans/sec //average number of transactions handled by server
Throughput: 0.01 MB/sec //average number of bytes transferred every second from the server to all the simulated users
Concurrency: 2.73 //average number of simultaneous connections, a number which rises as server performance decreases
Successful transactions: 20 //number of times the server returned a code less then 400. Redirects are considered successful transactions.
Failed transactions: 0 //number of transactions which didn't go through
Longest transaction: 4.25
Shortest transaction: 0.00

It is also possible to load test using a list of urls, and make the simulation closer to real cases. For instance:

siege -c5 -d5 -t10S -i -f sites.txt


-i is an option for internet user simulation, and hits URLs from the file randomly.

-f indicates that we should get the URLs from the file sites.txt. Each URL in the file should be on a new line.

There are many more options available which can be used, if required, based on different test cases.

-b is usually used to ignore any delay between requests for benchmarking purposes. If omitted the default is set to 1 second.

Type siege to get more details about the other options. More information can also be found here.

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