How to keep track of external hard drives? I have about 7 external hard drives of varying capacities. From time to time, I move files from my MacBook onto those external drives and put Finder aliases where those files used to be. The process usually goes down like this:


Move file in internal drive to the external drive.
Hold Cmd + Option and drag the file from external drive to the original location, thereby creating an alias.


Months later I don't recall which file is on what drive. Keeping a note around to write that down is tedious. Is there any app that keeps an inventory of disconnected external hard drives?
This is an interesting (as in unique, but not something I would personally do) way to store files.

My first thought would be to use colored tags.


Put a colored label on each of your external drives
Tag the aliased file/folder with the color associated with the drive's colored label.


Below, I created a folder alias (Music) from a USB drive to my desktop then  I tagged the folder with the red tag to correspond with the color coded USB drive.  





The colored tag on the folder alias will tell you which drive the alias resolves to.

You can even use multiple colors on the tag if your drives go above 7.  Here I have blue, orange, and red tagged.



You can find more information on how to fully use Tags from the Apple Support Document:  OS X: Tags help you organize your files