1st of all - Nine months of data in such cases would eat up lots of CPUs, I/O and memory 
.
However, reading should be easy if filters are used smartly. You cannot load a 500 gig file for reading. Also, the sum of all files should be 500 gigs per application server, so 500 gig is already segregated at OS level. All is need to do the same from SAP level using filters.
If your officer is still not concerned with after-effects, give him the access in non-business hours.
For rest, Deepak has already answered your query,
Regards,