Chuck van der Linden

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707 reputation
28
bio website resolvedtotest.com
location Maltby, WA
age 52
visits member for 2 years
seen Nov 16 '11 at 1:07
stats profile views 17

Just your typical software testing Sci-fi geek. (if there is such a thing. Been working with computers since the mid 74's, and doing so professionally since the early 80's It's been a long journey from the days of acoustically coupled modems, teletypes, and programs stored on punch-tape

Interests are: Agile Testing; BDD/ATDD; performance and load testing; Webtest UI automation via Watir and Cucumber; Virtualization of testbed systems using Hyper-V.

Also a bit of a hardware geek, building all my own systems other than laptops and tablets, as well as the occasional floating-arm trebuchet enter image description here when I feel the need to have fun sieging the castle or flinging a pumpkin or two.


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May
19
 awarded  Supporter
May
19
 answered How do you fit regression into Kanban?
May
19
 awarded  Organizer
May
19
 answered Should you preload DLL's in performance tests?
May
19
 revised How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
tag edit, added load-testing
May
19
 suggested suggested edit on How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
May
19
 revised How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
added link to free perftesting book
May
19
 comment How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
I've provided an answer below, but feel free to ask questions and I can try to clarify it. Or if you want to edit your original question and provide a few more specifics, such as how long on average each user interacts with the site, what the peak active users is during the hour and the total number of users interacting within the hour, then I can try to create an example where the numbers more closely fit what you are doing.
May
19
 awarded  Autobiographer
May
19
 revised How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
grammar
May
19
 awarded  Editor
May
19
 revised How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
bit more polishing
May
19
 comment How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
Also as another note, I try to stay away from 'hits' because that's sometimes hard to quantify in terms of how many users that represents. 'visits' if you can get it might be a better stat than hits. (after all, depending on the design, some web pages can generate between 20-60 or more requests JUST to load all the contents of the homepage, and some stats count each request as a 'hit' which can be very misleading
May
19
 comment How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
when discussing load tests, it's very important for you to define what you mean by 'simultaneous'. Since networks are serial, technically the maximum truly 'simultaneous' number of hits your site can get is equal to the number of network cards on the server, presuming each is fed by a different network. Also since what users do usually takes time. In your case it sounds like you've defined that to be 1000 sessions, but we still don't know how long each of those sessions is actually active, which is important.
May
19
 answered How do you calculate the number of virtual concurrent users to use in a load test given data on actual site traffic?
May
12
 awarded  Teacher
May
12
 answered Is a distinction between “testing” and “checking” useful?
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