Time for collection enable

Dear All,

We need to enable collections on EV partition. We have 4 partitons out of which one is open. The total Ev data is around 7 TB. Can any one inform me that , thow much total time EV will take to enable collections on EV data.

And most importantly, do we require backup of EV before enabling EV collection for 7 TB of data?

Thanks,

MontoN,