How to git fetch efficiently from a shallow clone

Question

We use git to distribute an operating system and keep it upto date. We can\'t distribute the full repository since it\'s too large (>2GB), so we have been using shallow clon

Answer 1

Note that Git 1.9/2.0 (Q1 2014) could be more efficient in fetching for a shallow clone.
See commit 82fba2b, from Nguyễn Thái Ngọc Duy (pclouds):

Now that git supports data transfer from or to a shallow clone, these limitations are not true anymore.

All the details are in "shallow.c: the 8 steps to select new commits for .git/shallow".

You can see the consequence in commits like 0d7d285, f2c681c, and c29a7b8 which support clone, send-pack /receive-pack with/from shallow clones.
smart-http now supports shallow fetch/clone too.
You can even clone form a shallow repo.

Update 2015: git 2.5+ (Q2 2015) will even allow for a single commit fetch! See "Pull a specific commit from a remote git repository".

Update 2016 (Oct.): git 2.11+ (Q4 2016) allows for fetching:

• since a date --shallow-since=
• up to a commit --shallow-exclude=
• with a greater depth: --deepen=N