DFT, minimize disk usage

Hello, I’m new to PSI4. I’d like to run a few geometry optimisations of not-so-huge systems (130-150 atoms) using GGA functionals. I am concerned that PSI4 creates huge scratch files (>95 GB and counting) and the SCF loop takes ages to even start.
I am using a 16-core VM via a cloud provider. My system has 634 electrons and 2976 orbitals (I’m using def2-TZVP basis). This is my input:

memory 10 Gb
molecule = { …}
set basis def2-TZVP
optimize(‘B97-D’)

What settings would you recommend to test for systems of this size?

I would be very grateful for any advice.
Best,
Michal Krompiec
CQ

Currently we have no direct DF-SCF code, though work on that is on the way.
Right now all DF integrals are written do disk unless they fit all into memory.
Then chunks of integrals are read and processed. Thus the code benefits from large amount of memory.

While writing all integrals to disk is slow, the SCF iterations will be fast unless the cloud provider has very slow disk access speeds.