Weird storage space issues

[Guest doveman]

I'm very confused about the storage on my Moto G 2nd Gen 2014, running stock KitKat.

I've factory reset now (I'll come to that later) but before, when I looked at System Settings - Storage, for the Internal Storage it showed Total 5.51GB, Available 1.08GB, Apps 6.06GB (what!), Pictures 7.09MB, Audio 220KB, Downloads 24.49MB, Cached data 389MB, Misc 316MB.

I was using the Xposed module obb2SD to move my game obbs to my external SD, so perhaps it still considered those on the internal SD and that's why the Apps alone showed as more than the entire space available. That does rather defeat the point of moving the obbs though if the system is still going to consider the space they use as allocated on the internal SD and thus not available. I also had a /sdext partition used with Link2SD, so maybe it was including that as well.

Link2SD - Storage Info showed the same 5.51GB Total, 1.08GB Available for Internal (/data) and SD Card (/storage/emulated/legacy).

In ES File Explorer's Homepage, it showed the same 5.51GB Total and 4.43GB Used for my internal SD (/storage/sdcard0 or storage/emulated/0). However, it seems that although the Homepage refers to and links to /emulated/0, it's actually showing the Total and Used space for the entire internal storage from / (root) here, as the total used in /emulated/0 was only 735.78MB (with Root Explorer and Show Hidden Files enabled). The Homepage should show and link to / if it's showing the space from /, not /storage/emulated/0.

Anyway, after wiping data and dalvik-cache (i.e. factory reset), TWRP showed about 370MB out of 5.51GB used. After booting, this was about 560MB (I guess due to the dalvik cache repopulating, which was 258.98MB at that point) and by the time Google Play had finished updating the pre-installed apps, this had risen to 1.27GB.

The majority of this, 1.17GB, is in /Data. Settings - Storage shows 4.24GB out of 5.51GB available.

I've found /data/data and /data/user are alternative paths to the same place, containing 230.99MB at present, which results in it getting counted twice, so really there's only a total of 965.51MB of files in /data, not 1.17GB. Obviously as /data/data grows, that's going to result in even more space being doubly allocated and thus unavailable, i.e. if I have 1GB in /data/data, it's going to reduce my free space by 2GB. Is this a bug in KitKat or does it just affect the Moto G 2014 2nd Gen?

I also notice that /data/app contains all the apks for the apps that are installed. I thought apks were just install packages, like Windows msi or exe installs and that when installed they unpacked to somewhere, so isn't it just wasting space keeping all of the apks here? It's only 357.19MB at the moment but when I checked it before I factory reset it was at least 1GB, so that's obviously a lot of space to waste out of 5.51GB.

I'll have to move my game obbs when I re-install them as the internal storage is too small. I might buy Link2SD as the Pro version of that says it can link obbs now, although it's probably not as convenient as obb2sd as it will need me to move/link each game one at a time, whereas obb2sd lets me just move all the obbs with ES File Explorer and then finds them automatically. It did have an issue where Play Store would crash when trying to update the obbs though and this could only be fixed by disabling obb2sd (which required a reboot), which then meant the updated obbs had to download to the internal SD again, then moved to the external SD and then obb2sd re-enabled (with another reboot), so hopefully Link2SD doesn't have that problem.