XF 2.1 XenForo's Scalability

Arnox

Member
I've poked around a little bit on Google to see what XenForo's theoretically performance limits are, but I can't really find anything. And especially nothing official. So obviously XenForo is built to scale well and it seems to do a great job of it, but how MUCH exactly can it scale before some large performance issues start to arise (for example, loading times for threads that take 5 seconds or more)? How many threads is it built to store, recall, and edit quickly? How many concurrent user requests can it support before it begins to lag heavily (5 seconds or more)?

For the server hardware and connection itself, if we need it, let's just assume our server is using a standard SSD with unlimited capacity, 4 cores at 2.4 GHz, 4 GBs of RAM, and 35 megabytes per second up and down speed.
 

Solidus

Well-known member
but how MUCH exactly can it scale before some large performance issues start to arise (for example, loading times for threads that take 5 seconds or more)?
I have a thread with 196,000 replies that loads no slower than any other, so where the performance issues (if any) begin is unknown to me.
 

Arnox

Member
I have a thread with 196,000 replies that loads no slower than any other, so where the performance issues (if any) begin is unknown to me.
I took a look myself. Yeah, just like my site, the custom thread sorting is incredibly snappy. Bringing that particular massive thread up is snappy. Even telling it to go to some arbitrary page in the huge thread loads the data in an instant with zero issues. All this just makes me even more interested in what XF can handle.
 

Kirby

Well-known member
Hmm, I don't think anyone has yet hit a case where a threads does take more than 5 seconds to load.

I'd be pretty surprised to see any real-world stock XenForo (eg. without Add-ons) that would take this long.

BTW: An SSD with unlimited capacity does not exist, everything is limited.
 

Chris D

XenForo developer
Staff member
The only known performance issue would relate to forums that have a very large number of nodes. This can cause the forum list to load slowly, and it can cause permission rebuilds to run slowly. But it still requires several hundred nodes to be an issue. It's debatable whether that many nodes is actually detrimental to a user's experience.

So, on the whole, XF itself should be very scalable and given that we have forums that have in excess of 50 million posts coping well, I feel confident enough to say we could cope with much bigger!

Indeed a comment was made about threads with large numbers of posts. This was a problem in some other software. You may have seen older forums where they would routinely branch off large threads after, say, 1000 posts. The way we handle our pagination and calculate post positions is what makes our threads effectively infinite in scale.
 

Mr Lucky

Well-known member
I have a thread with 196,000 replies that loads no slower than any other, so where the performance issues (if any) begin is unknown to me.
I'm not sure if this is still the case, but it used to be if all the replies had media (especially video) then this could slow things down.

@Chris D can correct me but I think this has now been dealt with in xf2 ???
 

Chris D

XenForo developer
Staff member
That's unrelated to scalability.

It's not a XenForo performance issue. It's really just a side effect of the page you're viewing having lots of external elements to load so that really just takes as long as it takes.
 

Arnox

Member
Excellent! How about requests and sending to users? How many concurrent users could XF theoretically handle given the specs above?

Also, is there any way one could make XF handle hundreds or even thousands of nodes with the equivalent performance it has when handling threads?

BTW: An SSD with unlimited capacity does not exist, everything is limited.
I know. This is just hypothetical. lol
 

Mr Lucky

Well-known member
That's unrelated to scalability.

It's not a XenForo performance issue. It's really just a side effect of the page you're viewing having lots of external elements to load so that really just takes as long as it takes.
That's right and I remember now the issue was when Youtube used Flash. There was a a custom bbcode needed in order to stop them preloading but I think it was you who pointed out this was no longer necessary anyway after they switched to html5
 

Chris D

XenForo developer
Staff member
Ahh that now rings a bell so, yes, sorted for the most part though fair to say that a significant number of embeds could add some overhead but certainly not as bad as the Flash days.
 

Mr Lucky

Well-known member
Ahh that now rings a bell
This is probably the bell that got rung...

 
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