[[!comment format=mdwn
 username="joey"
 subject="""comment 4"""
 date="2018-08-02T16:58:45Z"
 content="""
Parallel downloads will use the cache repository for everything if it has a
lower cost than other repositories. That's why the cost is set to 10 in the
example. If it has the same cost as another repository, parallel downloads
will spread the load between them. (This also means you can have multiple
caches with the same cost and distribute load amoung them..)

You should never be pulling from the cache repo, so there should be nothing
to merge from it. That's what the remote.cache.annex-pull is there to prevent
git-annex sync doing, but you also have to avoid pulling from it yourself.

Using tunables with the cache does seem to work. Since all remotes usually
have the same tunables as the local repo, there could potentially be
bugs (or optimisations?) where it applies the local tunables to the
remote, but in a little testing it seemed to work.
"""]]
