After configuring my hAP ac2 I discovered that almost all my free space was gone (see picture).
Although I have stored zero files, I only have 21% free space.
I already tried a factory reset, but that does not recover the free space. How can I recover all free space?
(hAP ac2, firmware 6.42.3)
PS: I did have a huge list of static DNS entries (> 10.000), but I removed most, now I have 322 entries left. May be relevant, maybe not.
That’s quite normal when non-volatile storage of a computer is only 16MB … what you see under /file is not the whole disk, it’s just the part you can access. On my hAP ac2 (ROS 6.43.1) it shows 3008kiB free (that’s less than 3MB), so you actually have more free space than I have. To whom can I complain? 
Hi mkx, no need to complain, just take out your wallet and invest in the 4011 
Problem solved, I take donations!
Actually I’m a believer in simplicity … in a sense that the best gadget is such that performs only a few functions, but those to perfection. So I’ll invest in a few hundred GB of SSD and put it into dedicated file/DLNA server … and voila, I won’t miss more space on my 'ac2 any more. I don’t need the ugly beast to shift those 30Mbps through VDSL line I’ve got.
Unfortunately, all these models with 16MB storage end up like this. Just system package alone takes 7.5MB of space, then you have all additional packages like wireless (2MB!), advanced tools, dhcp, routing, security etc etc…
In order to get more storage, I usually replace default bundled package with separate packages. That way I can install only what is really needed. Typical soho AP (i.e. pure L2 bridge of Ethernet and Wifi) for example does not need MPLS, PPP, Routing, Hotspot, IPv6 etc… Ta-daaaa… suddenly you got 1MB more!
Fortunately, there is USB where you can plug flash drive so you can get much more space for some files.
For Board with 16Mb use netinstall only.
It has checked by hAP mini.