Mail Folders as sparse images?

Question

There was a discussion on this issue a couple of years ago, but I'd like to check if anyone has tried it.
The problem:
20 GB of mail history that I would like to keep on line and accessible; however only the current year's folder changes
128GB MacAir disk that is getting close to full
The potential solution:
.Close mail
.Create compressed sparse images for the two large historical mail folders
.Move the folders into them
.Create symlinks from the original locations to the sparse image contents
.Automount the sparse images at login
I can foresee some potential problems:
.If I  forget and put mail into my startup items, I'll create a race condition that, if mail ever wins, is likely to corrupt the mail folders
.I better not unmount the sparse images while mail is running (ideally, I'd like to lock the mount, but I don't know any way to do that)
I'd appreciate any advice, especially from anyone who has already done something like this...
     Best Wishes
     Bob

Answer 1

That idea makes no sense. If you want to compress your old mail files, use something like afsctool (free) or this:
Clusters: Seamless File Compression