I have two fresh Galaxy device on Android 9 , the difference is in storage , one is 512GB and another is 128GB. System usage in both is different , 128GB version uses 27GB on fresh but the 512GB version use up to 47GB. There is no installed app and both devices are just out of box.

My question is why Android uses more storage on 512GB version and how can I decrease the amount? If it's dynamic what's the reason and should it decrease if the device is out of storage?

I don't want to root both devices, so I checked it on another device which is previously rooted. By df -h I see it's about device partition, the rooted device is 32GB out of which only 25GB is available. Other partitions are listed as below:

enter image description here

As you can see there is some duplicate mounted partitions , but sum of their sizes will be 32GB.

  • 2
    Root both and take a comparison of du -h /data | sort -h. Commented Jul 6, 2019 at 7:59
  • 1
    Check the partition size using an app like DiskInfo. On Android the system has on own partition. If the partition is larger the free size for user data is smaller.
    – Robert
    Commented Jul 6, 2019 at 11:34
  • 2
    @Robert df -h would also do the job. Just because eMMC is larger, could /system be larger on the same model? Shouldn't only userdata differ, that's what custom paid extra for. Commented Jul 6, 2019 at 23:01
  • Would you consider sharing your results? I just asked a very similar question here: android.stackexchange.com/questions/244678/… Thank you :-)
    – Jens
    Commented Jan 5, 2022 at 14:19

1 Answer 1


With root take a comparison of space usage on both devices by executing du -h /data | sort -h. Without root you can rely on figures reported by filesystem by running df -h.

From the updated screenshot you have attached, no partition is duplicate mounted. If you are talking about tmpfs, it's a volatile filesystem which lives in RAM and is vanished on reboot. It isn't part of your persistent storage.

Your /data and /system added make 29GiB. That's what you get on a 32GB device. Up to 2GiB difference comes because of Gigabyte (GB) and Gibibyte (GiB). Also there are usually 50+ partitions on an Android device which aren't mounted (except a few filesystems). And there's free space left by manufacturers for over-provisioning of flash memory.

For details see: How disk space is used on Android device?

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