Many people here found App2sd is not worthy for their huge number of applications, so they are left with Data2sd only.
Here is a quick “how-to” enable/disable Data2sd tutorial which is very easy to do:
– a secondery ext4 partition on sdcard.
How to enable:
1) if you have installed App2sd script delete it from /system/etc/init.d
2) flash any fugumod kernel.
3) create a file & write “mmcblk0p2″ in it and rename the file to “fs.data2sd”
4) move that file to /sdcard/Android/data/fugumod
5) restart the phone.. then check ur internal memory..
How to disable:
1) just delete the “fs.data2sd” file from there..
***if it feels like lagging, just have a swap partition on your sdcard & install swap script. This tutorial was tested on Samsung Galaxy 3 (Apollo)
Full credit to Ranadip Biswas