### Please describe the problem.

I'm running git annex sync <remote> sync'ing a local direct mode remote to a local indirect mode remote.

As part of this process, git annex is running git pack-objects --keep-true-parents --honor-pack-keep --non-empty --all.

This eats all of my raspberry pi's ram for lunch.  I think it even starts swapping, which would explain why it never seems to complete.

It's unclear why this is eating all my RAM, as I don't think I used to have this problem, and my repo didn't recently dramatically grow in size.  (I added < 100 multi-gb files, but that shouldn't make a difference here, I think.)

Anyway It would be nice if there were a way to get git-annex to pass a sensible -window-memory here.  I'm trying to use a wimpy machine, but I'm sure this could be a problem on a bigger machine too.

### What version of git-annex are you using? On what operating system?

$ git-annex version
git-annex version: 5.20141024-g613f396

$ uname -a
Linux raspberrypi 3.18.5+ #744 PREEMPT Fri Jan 30 18:19:07 GMT 2015 armv6l GNU/Linux

> [[done]]; not a git-annex bug AFAICS. --[[Joey]]
