There are many ways to copy/archive directory trees full of files under Linux.

For a typical Bitcoin full node operator, I'd recommend rsync:

https://serverfault.com/a/43019

... though even simple `cd $DESTINATION && cp -ax /full/path/to/existing/datadir .` (where . is the current directory after the cd command) should be sufficient.

rsync is likely to be a bit faster and more robust — and it can also handle remote sync'ing. (It's right there in the utility's name).