Maybe I'm just being cheap, but... I have a drive clotted with nearly 3TB of camera originals from a project from last year. The client asked me to keep the original drive they sent me, just in case. They have a copy of the media at the office. Their drive died.. and, as a courtesy, I was able to copy the files onto one of my working drives and finished the project on that. Now I need that space, and don't have another drive to put it on. So I can buy another drive and put it there (but I don't want to charge it back after all this time). Or... can I compress it, zip it, somehow in safe way that will be reclaimable later? Thanks for any advice you may have.
Since the camera already compressed the data, the only option to save further space is to transcode it to a lower, and lossy format.
Or, while it's more outlay, you could consider digital tape (LTO) for all of your off-lay operations. Your initial cost is a bit more than another disk, but with LTO-6 tapes running under $30, you're looking at secure offline storage of less than 1¢ per GB.