Hello, I'm using LimeSurvey 2. I looking for new hosting services which is able to expand to many survey takers at the same time (say 100,000). What is hosting configuration which can handle it? Please give me advise or reference hosting services. Thank you.

Do you mean 100.000 survey users at the same time? That's really a lot.

Have a look at www.limeservice.com .

100.000 concurrent connections with Limeservice? The last time I checked the TOS there where no service level mentioned. Some SaaS survey platforms are putting limits in form of abuse limits e.g. 1000 surveys per day. After that a dedicated server is used per user account.
@hoatamus:
How do you got the 100.000? The thread subject states connections, but in the post you talk about users. Connections, requests, and users are all different things. I don't see Limesurvey handling 100.000 concurrent users well. Would be interesting to see how the sessions are working when using file based session files which are very big since Limesurvey is putting too much in it.

Peak requests per second would be a technical term to ask hosting firms about there setup and performance of webserver and database server. The usage patterns will be different depending on the survey design. But still a lot more homogeneous in a survey than on a forum website (search, upload, post).

Please consider the option of a hosting company with in-house support staff trained for... firefighting :lol:

I think most survey systems will at least have some struggles when having to deal with actual 100.000 concurrent users. I agree with Jelo, most SAAS survey tools will limit what you can throw at them in some way.

And to be honest, I highly doubt that there will be actually 100.000 concurrent users, as long as you are not inviting 1.000.000 people at the same time.

If you mean that you need to complete 100.000 questionnaires/responses, then I would suggest to time the sending of the invitations in some way. Because even a standard dedicated server will have some trouble to handle huge loads of respondents at the same time (also because of the big session files of Limesurvey, but not only because of that).

So give us a little more information so we can understand your real needs. If your real need is 100.000 concurrent survey respondents, then I guess no one here has experience with this load.

jelo wrote: ..... handling 100.000 concurrent users well. ...

Even CMS can have issue with 100.000 concurrent users

DenisChenu wrote: Even CMS can have issue with 100.000 concurrent users

I have yet to find a CMS which creates a 1MB session file on a first visit. The whole session handling in connection with a post/get mix to allow catching forward / back page via browser navigation and browser crashes are an area for improvement.

Okay, let's see what we can do.

Limesurvey 3 (which is not even in alpha yet) will significantly improve in several areas:
1. Smaller sessions (no longer using sessions as a cache)
2. Real caches (that can be shared per survey instead of per session)
3. Javascript cachable surveys (the survey structure is cached both server side as well as client side and only filled with values during survey taking).

That being said, 100.000 concurrent connections is still too much for any normal setup (of any PHP app) to handle.
Suppose we have 100.000 users doing a survey at the same time, assuming they take approximately 20 seconds to complete a page.
At any second this means 5.000 users are pressing submit.
Assuming the page load time is < 0.1 second (which it is probably not), we have to do 50 seconds of processing time every second. Which means we need 50 cores and 50 php cgi processes (Assuming we run PHP-FPM).

If the requirement is real then there is a simple solution that will work for any type of web application: load balancing. Set up redundant systems and redirect users to one of these.

In general some optimizations might help, but load balancing will always be required to some extent.
- Use PHP-FPM
- Use the latest PHP version
- Use a memory cache (like memcached)

A more experimental but significant performance improvement can be realized using ReactPHP, this will move the bottleneck from CPU to Memory which scales more easily. (Note that LS2 is definitely not ready for this, but LS3 mostly is)

Regarding the request for firefighters, I am available for those kind of jobs, however note that, just like real firefighters, I will try my best but I cannot guarantee your house won't burn down

Contact me via skype sam_mousa for any inquiries!

sammousa wrote: ....
That being said, 100.000 concurrent connections is still too much for any normal setup (of any PHP app) to handle.
....

even without PHP, surely 100.000 concurrent connections to download a little picture take a long long time .....