HI subhasis,
I'd suggest you to make a few copies of your data at different locations.
First could be a local copy in the same place or in the same office. The second could be on the NAS server. For the third copy, you may use a cloud service.
Again, making a lot of backup locations comes with a cost too, but if you have the money to spend, and the particular data is quite important, then it's always safe to do so.
Specifically mention about sensitive data and want to reduce data leakage, then I would advise to do a proper homework on the cloud providers that you may ultimately choose.
Data leakage itself, though, could be a separate topic by itself and may be more related towards information security. For example, most data leakage in companies comes internally, like dissatisfied employees who have access to the sensitive data, copying them directly from the source.
Hope it helps.