Concurrent User Limit - WAS

[jkwrpc]

In a different thread someone was asked about an application being too big for the Alpha platform. Steve Wood, response was one that made sense to me but left me hanging. I have heard several times that the Alpha WAS can efficiently handle 'x' number of concurrent users. What I have never seen is what that 'x' is as a number. We know for example that MS Access was considered overloaded when there were more than 20 users. That number may vary depending on source but it gives you an idea of limits. Is there a similar generally accepted concurrent user limit on the WAS and if so what is it? Has that limited changed or been impacted with each of the releases from say v.9 to the current version 11.

While this is a serious question it is solely asked out of curiosity; I am not currently developing any web based solutions in Alpha.

[Lenny Forziati]

Re: Concurrent User Limit - WAS

X is extremely difficult to define because it is entirely dependent on the specific application, use cases, server hardware, and network and Internet connections. We could publish an optimistically high number based on a very simple application and disappoint users with more complex applications, or we could publish a conservatively low number using an aggressively complex application and sell ourselves short. There are just too many variables to be able to publish a number that is meaningful.

It is also worth noting that the difficulty in providing an answer is not unique to the Alpha server - it is common across any browser-based application platform. The more clearly defined X for Access was possible because of the constrained desktop-based architecture of it, just as it was possible to more clearly define X for an Alpha Five desktop application.

[gmeredith17]

Re: Concurrent User Limit - WAS

Hi Lenny,

Could you tell us your personal opinion on the amount of concurrent users based on a mid range server specification for your optimistic and conservative scenarios. I think it is just to give a general order of magnitude of Alphas capabilities.

Thanks

Geoff

[SNusa]

Re: Concurrent User Limit - WAS

Hi Lenny,

Could you tell us your personal opinion on the amount of concurrent users based on a mid range server specification for your optimistic and conservative scenarios. I think it is just to give a general order of magnitude of Alphas capabilities.

Thanks

Geoff

I'd like to have that a reference point in my head too: An "as few as" and an "as many as" (extremes) would provide a "vague sense of awareness."
(And it's the "as few as" that is most useful here IMHO.)

[jkwrpc]

Re: Concurrent User Limit - WAS

Lenny - thanks for the response. I will assume someone has done some load testing of WAS and perhaps can report how many concurrent users it was/is able to support. Again I am just curious but for others it may be useful information and impact how they design their applications.

[kkfin]

Re: Concurrent User Limit - WAS

It debends are you using Was as an application server or web server or as a compination.

If you are using Was in a public Internet I think it needs more cabable server as a frontend. I think this is a very common practise with many servers to have a more cabable frontend server(Nginx, Litespeed as an example). I use Abyss X2 as a reverse proxy to Was. That means that all traffic to Was is coming and going trough Abyss.

This gives some advantages. Abyss handles all SSL traffic to and from WAS so Was don't ssl any traffic at all. Abyss serves pure HTML content. This means that when more html content is needed an ajax callback happens and content is served directly from Abyss not from WAS.

Abyss has also built in firewall and much more choices for example to control directories and users.

Because Abyss is a reverse proxy to Was there is no same origin problems with javascript. That means that content to WAS page can be server from Abyss and vice versa using javascript (xhr object). My backend is Couchdb and because Abyss is also reverse proxy to Couchdb I can serve data directly to Abyss or Was from Couchdb.

There is remarkable difference in performance with this solution compared to pure WAS install in my opinion.

[jkwrpc]

Re: Concurrent User Limit - WAS

Ken

I am surprised that the performance improved with the Abyss implementation. I would have suspected adding another layer would have had the opposite effect and that WAS would have performed better without it. I wonder why that is, perhaps WAS is better at rendering the A5w page than it is as an public facing connection point.

Interesting and thanks for the post.

[kkfin]

Re: Concurrent User Limit - WAS

Abyss don't make Was a bit faster or slower. For example Google.com is not just one server, there is many many servers( or layers as you did make it) which share the workflow. Together these servers are faster than the one Google server alone.

And that how it also works here. Fast Abyss hides slow Was. But if you serve all content from Was as before everything is like before: there is no speed advantage of Abyss. The more faster this combination comes the more you deliver content directly from Abyss. Regular end user does no see that in fact there is two servers sharing load because together they make just one exactly same domain.