[Galaxy Tab Q&A, Help & Troubleshooting] giatros:
I thought about this idea while comparing my Android phone to my iPhone.

Both systems use variants of Unix, but the implementation is very different: there is one partition available to iPhone users, where all apps/music/everything gets installed. If you have a 64GB iPhone, this means you never run out of space for apps.

On the other hand, having a 16GB Android phone and a 64GB Micro SD puts you in a bit of a predicament, rather than a better place compared to the iPhone owner. Some genius has decided that there should be a 1-2GB /data partition where your apps go, and their data goes into the internal SD card; about 100-200 apps down the line (clearly, more than you need, but who are the android designers to judge), you run out of /data space and you end up doing ridiculous things like moving apps to SD, using some form of link2sd/data2sd script etc… Meanwhile you realise that your 64GB microSD is dead space and all you can do is store photos, music, video etc in it - rather than Asphalt data or Navigon maps.

This can change if you have a rooted phone! It took me a while to figure it out, but I first did it on my Galaxy Note N7000 following this guide: http://xdaforums.com/showthread.php?t=1887864 and then decided to create a new guide for my Galaxy Tab 7 (P1000). Credits to badge2033 for the first guide.

After following this guide you will have:

* supersized data partition (12 gigs): no more move to sd needed and then again the stock move to sd feature will work as expected (it will move data to the actual external sd card)

* external sd card mounted as internal sd card: nothing to say here, just does what is expected

* real internal sd (ums partition) shrunk to minimum (half gig) because it needs to stay present: used to mount a swap file (optional)

What you will need:

* Rooted Galaxy Tab P1000 - hopefully running Android 4.3 HumberOS CyanogenMod, but not necessarily (this guide is made with CM10.2 in mind)

* Working knowledge of ADB / Google to get you through bits if you get stuck

/* Standard disclaimer: Your warranty is now void. Use at your own risk.
Modifying or replacing your device's software may void your device's warranty,
lead to data loss, hair loss, financial loss, privacy loss, security breaches, or
other damage, and therefore must be done entirely at your own risk.
Every time you do not backup and complain a puppy dies.
No one is responsible for your actions but yourself. Good luck. */

Procedure:

1. reboot to recovery, and connect your phone to your pc

2. run a command prompt and type the following (wait a little bit until the adb server starts on the phone, you can verify it by typing "adb devices" if you get a serie of digits then you're good to go.

adb shellcat /proc/partitions

You should see something like:

31 0 7680 mtdblock0
31 1 7680 mtdblock1
31 2 443904 mtdblock2
31 3 22528 mtdblock3
31 4 12800 mtdblock4
31 5 11264 mtdblock5
179 0 15552512 mmcblk0
179 1 13455328 mmcblk0p1
179 2 1994752 mmcblk0p2
179 3 102400 mmcblk0p3
179 16 1024 mmcblk0boot1
179 8 1024 mmcblk0boot0
179 24 31166976 mmcblk1
179 25 31162880 mmcblk1p1

Backup your /data to External SD. REMEMBER YOU HAVE ALREADY COPIED YOUR INTERNAL SD TO THE EXTERNAL ONE!!! I did a dd backup and a nandroid in CWM. You only need the nandroid to restore later.

dd if=/dev/block/mmcblk0p2 of=/storage/sdcard1/databack.img bs=4096

/*** WARNING!!! Do your own backups / nandroids /
write important things down on a napkin, if this does not work for you
and you lose data I'm not responsible!!! ***/

You should see something like:

498688+0 records in
498688+0 records out
2042626048 bytes (1.9GB) copied, 277.149450 seconds, 7.0MB/s

Then use parted, the partition editor:

parted /dev/block/mmcblk0

you'll get into the parted interactive shell, this is where serious work done

unit b
print

You should see something like:

Model: MMC SEM16G (sd/mmc)
Disk /dev/block/mmcblk0: 15925772288B
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number Start End Size Type File system Flags
1 32768B 13778288639B 13778255872B primary fat32
2 13778288640B 15820914687B 2042626048B primary ext4
3 15820914688B 15925772287B 104857600B primary ext4

did i remind you to backup your system,this is your last stop before the no back pointso you just might wanna "move" all your internal sd stuff to the external sd,and backup your system to the external sd also (you just need to restore the data partition afterwards the rest of the system is safe but who knows :p)ps: you can do your backup on cwm without leaving adb shell on the pc just like you will do the format later thanks to cwm

remove the partitions

rm 1
rm 2

make the new changed size partitions

mkpart primary 32768 536903167
mkpart primary 536903168 15820914687
print

you should see this output

Model: MMC SEM16G (sd/mmc)
Disk /dev/block/mmcblk0: 15925772288B
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number Start End Size Type File system Flags
1 32768B 536903167B 536870400B primary fat32
2 536903168B 15820914687B 15284011520B primary
3 15820914688B 15925772287B 104857600B primary ext4

Format the data partition as ext2 (so that CWM can see it)

mkfs

Then choose 2, ext2

now in cwm go to mounts and storage and select "format /storage/sdcard0" and "format /data"

now restore your data partition in CWM.

and you will be able to boot you system normally. and you go to your storage information you will find that your app storage is now 13gigs and the usb storage is just 500 megs yay

For Android 4.3 modifying vold.fstab file (but for other versions do so with ciphray's guide on how to do so)

you can use the modified file from ciphray thread here which i didn't beacuse his file was smaller

What DOES work is the free External 2 Internal app in Google Play: https://play.google.com/store/apps/details?id=eu.codlab.int2ext&hl=el

Settings are (for CM 10.2 ROM):

Original Internal mounting point: /storage/sdcard0

Original External mounting point: /storage/sdcard1

Ext.sdcard device access: /dev/block/vold/179:25

[Have not done this - badge2033 suggests it]

as a final step you can use the now pretty useless internal space (500megs remember) as a swap sapce

download swapper2 from the play store here https://play.google.com/store/apps/d...v.n3o.swapper2

run it and go to settings

set swap place as /sdcard/external_sd/swapfile.swp

set swap size to the max

set the swappiness to 20 ( you can rise the value a little but don't put a high value or the system will do much swapping all the time -value of 100 means any memory not used actively will be swapped- )

wait until the process finishes then reboot your phone

you can verify that swap is working by typing "free" in the shell if the line beginning with swap is not all zeros then you're swap is working.

Phew! That was a long guide. Questions / comments below.