Hello,
Question and Answers:
a. What will be required free space in system drive to update SEP client automatically?
For SEP clients, Hard disk requirements is 700 MB or more free space
b. Each client will store more than 1 definition. Can reduce it to one definition per day? Which SEPM policy needs to change for it?
On SEPM Default is 3. Incase, if you have Between 100 and 500 clients then minimum 3 revisions are recommended.
However, for SEP clients you could reduce it to 1 definitions per day from Liveupdate Policy to fetch updates once per day (daily).
c. If we manually delete virus definitions of previous days for free space, what will be impact on SEP client?
I see no issues with the same.
Hope that helps!!!