I just installed unfi controller (v6.0.43) and two UAP-AC-LR's with mesh.
Looking at the MAP function tab - it seems to be working well sharing connected devices on the AP's.
FYI - I am doing this as I previously had multiple wifi access points with different names to service my house and with new devices coming into the house such as wifi lights etc - i want to hang them off the same wifi network.

My questions are:

Q1

In my controller under ALERTS - it says "The UniFi Controller data partition is nearly full. Only 256 MB of 237 GB free".
Yet while 237GB refers to my M.2 C drive with my operating system - have more free space than this.
Any idea why the error message or how to allocate more space to the unifi data partition?
FYI - I have subsequent to installation deleted data from my c drive and the alert has gone away.

Q2

Also I have a vodafone ultra hub which I have connected the Unifi AP's too. Each has its own power block.
I saw PB Tech sells 

- Ubiquiti UniFi Switch US-8-60W 8-Port Gigabit Managed PoE Switch with 4 x PoE (Max 60W)
https://www.pbtech.co.nz/product/SWHUBI10081/Ubiquiti-UniFi-Switch-US-8-60W-8-Port-Gigabit-Mana?qr=related-view 

- Ubiquiti UniFi Security Gateway USG, Enterprise Gateway Router with 3 x Gigabit RJ45 Advanced FireWall, VLAN, VPN, Radius Server
https://www.pbtech.co.nz/product/NETUBI1156/Ubiquiti-UniFi-Security-Gateway-USG-Enterprise-Gat?qr=related-view 


However even after reading - I cannot see the purpose of these switches or if they would benefit me?
Can someone please explain whether I should also install a switch for my AP's?


Cheers