When I read some article it said Siege tool can accept 800 users concurrently. If so how can I simulate 1000 or 2000 users concurrently. Do I need more machines or can I run using multiple terminals?

when I run siege on multiple terminal -c500-d5 500 hits for every 5 seconds, at a time I run on the 2 terminal, but found that First terminal is running fine and other terminal gets fail,

1 Answer 1


From the Siege FAQ there is nothing to conclude it has a maximum of concurrent users, it does offer some advice, but not on increasing the load.

Keep in mind that -c256 -d1 translates to roughly 47,000 unique visitors per day.

Each physical machine will have a certain limit based on CPU, Memory and number of network sockets. Technically a single machine could handle 10K+ connections, in this question talks about 1,6 million simultaneous sockets connections on a pretty heavy machine.

Opening more terminals will probably not let you increase the number of connections on a single machines. You could just increase the -c number, until the machine gives an "Error: system resources exhausted" error or something similar. Experiment with what your machine can handle. Alternatively just try it and find out or ask the same question to the developers at GitHub-issues.

If you need more load with Siege I think you should just get more physical or cloud-machines to run it on, just start some scripts at the same time. Have a look at clustershh to send the same command to multiple machines at the same time if timing is important for you.

  • Read the documentation: joedog.org/siege-manual/#a02 -d is a random delay between 1 and 10 in your case. So it each connection waits a random time before connecting again. This means 1500 users will connect between 1 and 10 seconds and then randomly keep repeating the connection each 1 - 10 seconds. So some seconds it will be more users than others, but never more than 1500. Jul 4, 2017 at 5:54
  • So if I want to get the concurrent hit of 1000 users then I need to put the delay as 1 sec right ? siege google.com -d1 -c5 -t1s when I try this the output shows as Transactions: 2 hits Availability: 100.00 % Elapsed time: 0.58 secs Data transferred: 0.02 MB Response time: 0.44 secs Transaction rate: 3.45 trans/sec Throughput: 0.03 MB/sec Concurrency: 1.50 Successful transactions: 4
    – user24314
    Jul 4, 2017 at 6:04
  • -d1 and -c1000 could work yes, but I wonder what you are trying to achieve, because Siege seems not the tool for a controlled load-test. More a simple tool to hammer your server as a madman, but ask detailed questions. Maybe jMeter is a better fit for you as it is a completer load-test tool. Also I think your extra questions are good new questions instead of comments. Jul 4, 2017 at 7:10
  • It is a new question. Use the ask new question button. Jul 4, 2017 at 15:46
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    @PerLundberg You're totally right, edited the answer. Thanks. Feb 14, 2019 at 8:53

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