### Please describe the problem.

The assistant is using gruesome amounts of resident memory:

<pre>
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
www-data 23898 29.0 90.4 7842888 5536740 ?     Sl   Jun17 2810:08 /usr/lib/git-annex.linux/exe/git-annex --library-path /usr/lib/git-annex.linu
</pre>

I had to stop the assistant because it ended up using all memory.

### What steps will reproduce the problem?

Unclear. The assistant has been running for a while and there's a big tansfer (~800GB) of files in progress.

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

5.20150610+gitg608172f-1~ndall+1 on Debian 7 Wheezy.

### Please provide any additional information below.

daemon.log: http://paste2.org/YJVGvpy5 --[[anarcat]]
