Analog has the ability to archive some of the data in your logfile into a cache file so that the logfile can be thrown away without losing the most important data. That in itself may solve your filespace problems, without needing to throw away any information. The cache file is also not the best format for post-processing the data or feeding it into a spreadsheet. For that you should use the computer-readable output style .
Many people have trouble using the cache file, and end up accidentally recording corrupt data.
You do need to understand what you're doing before you throw away your logfiles. See the discussion on Procedures below. If you are going to use the cache file feature, it is also very important that you understand what is and what is not recorded. If you want different sets of options, you must create several cache files from the same logfile. The reason for this is that it is not possible to reconstruct everything of interest in the logfile from the cache file.