diff --git a/doc/forum/__34__best__34___portable_filesystem_for_external_drive__63__.mdwn b/doc/forum/__34__best__34___portable_filesystem_for_external_drive__63__.mdwn
new file mode 100644
index 0000000000..cf448fe057
--- /dev/null
+++ b/doc/forum/__34__best__34___portable_filesystem_for_external_drive__63__.mdwn
@@ -0,0 +1,3 @@
+question came up on [neurostars](https://neurostars.org/t/downloading-data-for-the-dartbrains-online-course/23430/7) and I had no good answer:  what would be the best filesystem to use on external drives which would be portable (mountable) across OSes and would provide git-annex with needed features (symlinks, permissions handling, and  locking?).
+
+I love BTRFS on Linux but I do not think it is (and neither ext* family) is portable.  Is there **any** filesystem which would be portable across Windows/OSX/Windows and still work with git-annex without needing adjusted-branches mode?