-# Max number of VM I/O threads running at the same time.
-# This threads are used to read/write data from/to swap file, since they
-# also encode and decode objects from disk to memory or the reverse, a bigger
-# number of threads can help with big objects even if they can't help with
-# I/O itself as the physical device may not be able to couple with many
-# reads/writes operations at the same time.
+# Hashes are encoded in a special way (much more memory efficient) when they
+# have at max a given numer of elements, and the biggest element does not
+# exceed a given threshold. You can configure this limits with the following
+# configuration directives.
+hash-max-zipmap-entries 512
+hash-max-zipmap-value 64
+
+# Similarly to hashes, small lists are also encoded in a special way in order
+# to save a lot of space. The special representation is only used when
+# you are under the following limits:
+list-max-ziplist-entries 512
+list-max-ziplist-value 64
+
+# Sets have a special encoding in just one case: when a set is composed
+# of just strings that happens to be integers in radix 10 in the range
+# of 64 bit signed integers.
+# The following configuration setting sets the limit in the size of the
+# set in order to use this special memory saving encoding.
+set-max-intset-entries 512
+
+# Similarly to hashes and lists, sorted sets are also specially encoded in
+# order to save a lot of space. This encoding is only used when the length and
+# elements of a sorted set are below the following limits:
+zset-max-ziplist-entries 128
+zset-max-ziplist-value 64
+
+# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
+# order to help rehashing the main Redis hash table (the one mapping top-level
+# keys to values). The hash table implementation redis uses (see dict.c)
+# performs a lazy rehashing: the more operation you run into an hash table
+# that is rhashing, the more rehashing "steps" are performed, so if the
+# server is idle the rehashing is never complete and some more memory is used
+# by the hash table.
+#
+# The default is to use this millisecond 10 times every second in order to
+# active rehashing the main dictionaries, freeing memory when possible.
+#
+# If unsure:
+# use "activerehashing no" if you have hard latency requirements and it is
+# not a good thing in your environment that Redis can reply form time to time
+# to queries with 2 milliseconds delay.