Backing up iTunes library (songs purchased and downloaded by CD)

Hi all,

A friend of mine did an update on his MacBook Pro (this was a while ago, so I'm not sure which update) and all of his music that he downloaded by CD vanish from his iTunes library and apple said they most likely can't be recovered.

Having about 3,000 songs in my library, I'm concerned that I may run into the same problem someday so would like to know how I could back up all of my music specifically the ones that I downloaded by CD as I no longer have the physical copies.

Is there a way to move all of my music onto a portable drive similar to how we used to move them over/rip CDs so I could send them back over to my mac/have access to them if they ever disappear? I was thinking dragging them onto something like Drop Box would work but I'd like to have them not only in the cloud.

Thanks!