+# By default, messages that are waiting on Exim's queue are all held in a
+# single directory called "input" which it itself within Exim's spool
+# directory. (The default spool directory is specified when Exim is built, and
+# is often /var/spool/exim/.) Exim works best when its queue is kept short, but
+# there are circumstances where this is not always possible. If you uncomment
+# the setting below, messages on the queue are held in 62 subdirectories of
+# "input" instead of all in the same directory. The subdirectories are called
+# 0, 1, ... A, B, ... a, b, ... z. This has two benefits: (1) If your file
+# system degrades with many files in one directory, this is less likely to
+# happen; (2) Exim can process the queue one subdirectory at a time instead of
+# all at once, which can give better performance with large queues.
+
+# split_spool_directory = true
+
+