If you are installing the current version of NTA then first of all the netflow data (most of it at least) is not stored in the SQL db, you set up a different server to house a separate non-sql NTA fastbit database. If you are sending 60 gb of netflow data per month and plan to retain a month of data then you can likely expect your NTA db to be pretty close to that size, most clients I work with have NTA db's in the 25-100 gb range. Raw netflow data is already relatively stripped down and is mostly metrics to begin with.
2 Since NTA is a Netflow collector you can relay your flows pretty much anywhere you want, as long as something forwards them to Solarwinds without hacking up the data in the packets.
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