Root Symbolically Linking Internal SD to External SD

[5paceManSpiff]

To give a little background on my experience with the android platform, I have toyed around with the sdk quite a bit, and am somewhat familiar with the structure of the platform. I had heard rumblings about using symlinks and some sort of script to link the two sd card portions on each reboot. I have done some preliminary testing with this, and would like to know if this has been done before? If not, is this something that others would like to have a guide on?

 

[Dark One]

There is an app called link2sd that does what you're talking about i think.

 

[5paceManSpiff]

There is an app called link2sd that does what you're talking about i think.

There have been varying reports on its success.

 

[kwknott]

On this phone there hasn't been luck with app to sd linking. I think the kernel needs to be modified to support an sd-ext partition for this to work.

The few times I trird a couple app to sd apps they couldn't properly detect the 2nd sd partition

 

[DroidMello]

I use a program called directory bind that works for data directories. It takes some work to setup but then it runs automatically. The XDA thread is at http://forum.xda-developers.com/showthread.php?t=1410262

 

[HallOfPromise]

That looks like just what I was looking for. However, the skeptic in me wants to wait until I hear from a few more noble souls who have given it a go at using it first. But so far it looks great!

 

[HallOfPromise]

So I gave DirectoryBind a try last night and ran into a weird situation. I tested out a bind to see if it worked but rather rerouting the data to the external SD, it seems to just be copying the data from internal SD to external, creating the bind on the external but also leaving and storing the same data in its original place in internal sd. Any help in getting this to work properly would be greatly appreciated.

Edit: Okay after binding larger folders and keeping an eye on used and free space it looks as this app works! I think I got confused earlier in thinking the app was just copying data because in file explorers the data can be seen in both the original file and new location. I think even the file explorers get tricked in leading us to the new location. Does that make sense?

 

[DroidMello]

I was going to respond but you figured it out already. With symlinks it will always look that way (appearing both in the original location and the new location) when linking is successful. This is how they function. Because the system will not allow things to be moved to the external sd card the only way to do so without MAJOR modification is to trick it into believing that the items are still in the original spot. That is exactly what a properly executed symlink does.

 

[HallOfPromise]

Well that is pretty cool. Thank you!

So far I have played around with the small stuff, like map cache and Play Music cache, just to see if it works. I had to change a few settings to get it to keep after rebooting, which is explained. However, I was hoping to use it for larger, bigger and better things.

Has anyone tried using this on the entire Android and/or .android_secure folders? I personally wouldn't mind keeping the apps (.android_secure) within internal sd for speed and booting reasons, but simply linking the Android folder to the external sd would save A LOT of space within internal sd. Is this a smart and safe thing to do?

 

[HaTrEd360]

I use GL To Sd which links Gameloft games to Sd card. I have Asphalt 7 which is 1.3gb's and it links it to SD card successfully. And that comes from the Android folder on Internal. I can imagine it having to run and use a lot of Ram to keep things mounted correctly for it to fo so tho but I'm not certain. I'm sure it's safe to do so since you're not really linking anything from the system itself. Make a backup of the data in your apps tho using Titanium Backup, just to make sure in case it crashes and you lose all your app data.