title: git-svn crashing on big repo migration
body: <p>I've been struggling for a couple of days to migrate a big SVN repo to GIT. It contains about 25000 commits, includes some bad history (moving huge amounts of files due to wrong attempts of branching), non-standard layout (no trunk folder, branches which are not branches in fact so I treat them as part of trunk, no tags...) 
  I started with Atlassian tutorial (<a href="https://www.atlassian.com/git/tutorials/migrating-overview" rel="nofollow">https://www.atlassian.com/git/tutorials/migrating-overview</a>)
  so basically what I'm doing is migrating SVN to GIT repo on my own computer for now. I'll push it to central repo later.</p>
  
  <p>GIT version is 2.7.2.</p>
  
  <p>I tried git svn directly and indirectly with svn2git (based on Ruby)</p>
  
  <p>I've tried multiple approaches but I always sooner or later get: </p>
  
  <pre><code>couldn't truncate file at /mingw64/share/perl5/site_perl/Git.pm line 1393.
  </code></pre>
  
  <p>or </p>
  
  <pre><code>0 [main] perl 12640 cygwin_exception::open_stackdumpfile: Dumping stack trace to perl.exe.stackdump
  </code></pre>
  
  <p>Any ideas are welcome... :)</p>
  
  <p>Thanks!</p>