Board Optimization - Dynamically Linked Source - Speed Up Your Multiple Site Network & Upgrades

For the purposes of this documentation, "Network" refers to a group of forums on a single server or cluster of servers.

When 3.7.1 PL2 was released, I posted over at vbulletin.com lamenting the fact that I had 15 upgrades to perform and how it would be nice to have a multiple site license to lighten the burden of downloading each install separately. In the end, I spent much more time coming up with this system.

Dynamically Linked Source or DLS allows operators of two or more forums on the same server or cluster, for all intents and purposes, to use one set of source code instead of multiple sets. By using one set of source code, Op code caching is much more efficient as only one copy of the source is cached. This greatly reduces the amount of memory used caching the source code, and also makes it more efficient. It will lead to less fragmentation for systems using APC, XCache, eAccelerator, or other such methods of caching Op code.

The method uses symbolic links to a central repository of the source code. Therefore, upgrades to all sites on the network can be done quickly by just replacing the source. For patch level releases, this means the entire network can be patched with one upload. Upgrades to a new version can be done this way, or a new repository can be created and each site can be upgraded one at a time.

The issue of licensing has also been addressed. Once the product file is installed, and assuming the installation instructions were followed, each installation will report the proper license key when salting cookies, or reporting back to Jelsoft as Vbulletin does from time to time (mostly in the AdminCP).

I contacted the development team at Jelsoft and discussed this method before releasing it, and got the OK from Mike. I was initially concerned that it may break licensing or perhaps give away too much of the license reporting methodology, but now that I look back, it really does not do either.

In tests on a rather large network that contains seven forums with about 7 million posts, hundreds of thousands of registered users, and uses three load balanced servers the load has been reduced by almost 40%. You can see in the graph attached to this thread for the particulars.

I have tried to make the readme as clear as possible, but honestly that was never one of my strong points. I cannot emphasize more that before you implement this method, TEST it first in your sandbox. Also, make sure you backup your software and database before you use this.

I also have included a PDF that explains what is happening in greater detail.

Updates:

8/20/08 - This will work with the latest version of VBSEO (3.2.0 at this time). Add all the files to the DLS except the config file, and run the php-clone.php script.

This product was developed for Andy R from Social Knowledge and released here for others to enjoy.


Please don't forget to click install as I have worked quite a while on this.

[Amenadiel]

this seems amazing, I'm just starting to understand its full extents.

By the way, I'm studying the integration of two boards. They are on separate webservers and I plan to have independents database servers for each of them. It seems this mod can help me combine both webservers so both boards can use one logical webserver which is the load balancing between the current ones, but won't help me integrate users and passwords since DBs will still be on separate machines, am I right?

[Jafo232]

Yes, that is correct. This will really do nothing as far as integration goes.

[993ti]

Originally Posted by Jafo232

You can link any file just by adding it to the DLS source and running the php-clone.php script.

So if 2 forums have the same products that required uploads, it's best to include those files?

[Jafo232]

Yes, you can add them.

[sdsvtdriver]

When referring to Windows, are we referring to Windows running IIS or Apache (or is it not relevant)? If Apache, would using the alias command work?

Alias "/site1/forums" "C:/htdocs/forums"
Alias "/site2/forums" "C:/htdocs/forums"
Alias "/site3/forums" "C:/htdocs/forums"

Has anyone tried NtFS link? http://sourceforge.net/project/platf...roup_id=161885

linkd? http://support.microsoft.com/kb/205524

[sockwater]

NTFS Link creates hardlinks and junctions and linkd creates junctions. Both of these have been confirmed to not work. Well, they work but they are cached as if they were separate files.

[Jafo232]

Yeah, I doubt there is a Windows solution that will offer any cache relief. Of course, you could always go Linux, but who wants to start that discussion!

[sockwater]

Originally Posted by Jafo232

Yeah, I doubt there is a Windows solution that will offer any cache relief. Of course, you could always go Linux, but who wants to start that discussion!

This might actually be a bug in the caching code that is not recoginzing Windows hardlinks/junctions in the same way it recognizes Linux symlinks. Since I use linux, I won't be pursuing this, but for those who have Windows servers, it might be worthwhile to submit this as a bug/feature request to APC/Xcache or whatever you're using.

[Jafo232]

If it happens with the big three opcode cache methods, I would then think it was something native with Windows. I dunno, not a .dll head here..

[ManagerJosh]

Just wondering, are users/members of each forum independent? Or are they linked?