Ceph

A customer mistakenly named a directory as his osd journal location; the failure printed to his terminal with no hint of the actual problem:

=== osd.0 ===
2012-08-11 03:10:23.967661 7f5cd260f780 -1 OSD::mkfs: FileStore::mkfs failed with error -21
2012-08-11 03:10:23.967701 7f5cd260f780 -1 ** ERROR: error creating empty object store in /srv/ceph/osd0: (21) Is a directory
failed: '/sbin/mkcephfs -d /tmp/mkcephfs.5ZBxofGW9l --init-daemon osd.0'

The critical message for understanding the failure is printed in FileStore::mkjournal,
but it's done with dout(0); it should probably be derr:

ret = journal->create();
      if (ret)
        dout(0) << "mkjournal error creating journal on " << journalpath
                << ": " << cpp_strerror(ret) << dendl;