Merge pull request #857 from GEOS-ESM/feature/mathomp4/mepo-advice

Add mepo blobless advice

README.md

@@ -155,6 +155,20 @@ Note that when you first use `gh`, it will ask what your preferred git protocol
 is (https or ssh) to use "underneath". The caveats above will apply to whichever
 you choose.
 
+### Setting up `mepo` to use blobless clones
+
+The GEOS GCM uses a Python utility called [mepo](https://github.com/GEOS-ESM/mepo/) to manage **m**ultiple git r**epo**sitories instead of using other technologies like Git
+submodules. `mepo` uses a YAML file that provides a list of components (and their versions) that are required for a particular configuration of GEOS GCM.
+
+We *highly* recommend setting up `mepo` to use [blobless clones](https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-shallow-clone/) to speed
+up cloning of the sub-repositories, especially on discover. To do this, there is a one-time command to run:
+
+```
+mepo config set clone.partial blobless
+```
+
+This will set up `mepo` to use blobless clones for all future clones by adding an entry to `~/.mepoconfig`.
+
 ---
 
 ### Single Step Building of the Model