Missing features:

* mb probefile: follow redirects. Testcase:
  http://distro.ibiblio.org/pub/linux/distributions/opensuse/factory/iso/openSUSE-NET-i586-Build0138-Media.iso
  which "blindly" redirects to an FTP server (by URL rewriting), but the file isn't there.

* mirrorprobe: does it deal with FTP urls entered as baseurl (which is meant for HTTP)?

* make ZrkadloExcludeNetwork work by prefix match, instead of simple string
  prefix comparison using apr_ipsubnet_create() and apr_ipsubnet_test() as 
  mod_authz_host does

* make installation easier, by providing Makefiles, and a setup.py for the Python module.


Improvements:

* rewrite debugLog(r, cfg, ...) as Macro which checks for cfg->debug==1 before
  caling ebugLog()

* check whether the maxconnections metalink attribute should be included, so that
  aria2c downloads from more than one server even when every server has a distinct
  preference value.

* add "md5" and "sha1" or "checksums" link to mod_autoindex_mb. Make it configurable so
  it can be switched off for the very large directories that are already slow
  to show anyway.
  In addition, the checksum(s) could be added into the mirror list. Would be highly useful.

  On further thought about this, I realize that serving the hash from the
  metalink-hashes-dir by appending .md5, would shadow existing .md5 files;
  likewise for sha1 files.  But it would still be worthwhile and it wouldn't
  matter I guess.

* ?mirrorlist mirror lists: set Vary header on X-AS?
  make it more cacheable?
  Cf. http://redbot.org/?uri=http%3A%2F%2Fdownload.opensuse.org%2Frepositories%2FApache%2FFedora_10%2FApache.repo%3Fmirrorlist
  Metalinks:
  make less cacheable?

* check if the Vary header on Accept is added on all requests!

Further ideas:

* evaluate if it makes sense to memcache database query results, which may not be
  practicable for all objects, but for some particular objects, like those with
  mime type application/x-cd-image. They should not be cached for a significant
  amount of time, but a few minutes shouldn't be a problem.
  As a key for the memcache object, one could use the label of the prepared SQL
  statement combined with the filename.

* add SQL_CACHE hints? do this conditionally?

* stickyness of (large) files to certain mirrors, to make better use of buffer caches?

* collect statistics on number and volume (cumulated file sizes) of redirects
  for mod_status, show per mirror identifier since last restart

* check whether usage of explicit ap_dbd_open/ap_dbd_close, instead of the
  ap_dbd_acquire wrapping function, results in better utilization of the database
  connection pool
  but apr_reslist is undergoing some fixes/changes currently (1.2.11 time), so let's wait