Putting together the numbers: server=2 ports (for each HCA) so 20 servers runs 40 ports (potentially).
36 ports switch is under the 40 limitation so no issues with that part.
i guess, for your purpose, CSV will work but here is another advise (and sorry i am not being specific enough):
from my experience, if you use the history feature to investigate an event that took place in the past, you usually have some idea about which elements were involved with the issue. Try to narrow down your data analysis only to relevant ports (as much as possible). It will make your work more efficient too.
Thanks