OpenShift deployment dir structure

gistfile1.txt

app-deployments
  2013-09-25_12-19-31.426
    repo
    dependencies
    build-dependencies
    metadata
      id (abcd1234, checksum of contents of this deployment dir (2013-09-25_12-19-31.426))
      git_ref
      git_sha1
      state (DEPLOYED, currently isn't changed if something else is deployed later)
  by-id (really by-artifact-id)
    abcd1234: symlink to ../2013-09-25_12-19-31.426
  history (single file)
    # deployment id (optional/hard to coordinate across gears?), date/time, artifact id
    1,2013-09-25_12-20-17.819,abcd1234
    2,...

app-root
  repo: symlink to runtime/repo
  dependencies: symlink to runtime/dependencies
  build-dependencies: symlink to runtime/build-dependencies
  runtime
    repo: symlink to ../../app-deployments/2013-09-25_12-19-31.426/repo
    dependencies: symlink to ../../app-deployments/2013-09-25_12-19-31.426/deployments
    build-dependencies: symlink to ../../app-deployments/2013-09-25_12-19-31.426/build-dependencies

which to delete?

app-deployments
  a
  b
  c
  history
    1,a
    2,b
    3,c
    4,a

git push, keep_deployments = 3
 creates deployment "d"
 need to delete 1 deployment so we stay at 3
 should it be "b" since the 2 most recent activations were "a" and "c"