I've been doing some testing of different methods for compressing and storing SQL Server backups (using SQL Server 2008 R2 Enterprise edition), and I'm wondering what the most effective compression algorithm is for long term storage of those backups, outside of SQL's internal compression algorithms.
I'm not worried about the physical storage or tape drives or anything, just trying to turn our 3TB of data and log files into the smallest single file I can.
So, for example, would a .zip or .7z? Or are there too many variables within my database to be able to accurately estimate what will be the most effective and I'll just need to do some tests? Or is SQL Server's internal compression the best I'll get?