Xperia XA2 is listed with 32GB internal storage.

Sailfish settings UI under storage shows for me some confusing numbers.

User data: 273.9 MB used, 17.0 GB free
System data: 1.1 GB used, 1.3 GB free

What happened to the rest of "32 GB"?

Does flashing Sailfish erase data Android partitions (and installed Android applications, besides the kernel / hardware drivers)? It looks to me like a lot of space is wasted somewhere.

UPDATE:

Ah, I think it's used for a lot of other mounts.

df -h also shows me such total sizes:

2.4G /
18G /home

6 different tmpfs (1.3G) and stuff like /opt, /fimage, /odm, and etc. So I guess the usage is legit.