title: After Redis cluster reshard, lots of non contiguous slots assigned to a node
body: <p>I created a redis cluster with three nodes:</p>
  
  <pre><code>~ redis-3.2.10/src/redis-trib.rb create 127.0.0.1:7000 127.0.0.1:7001 127.0.0.1:7002
  </code></pre>
  
  <p>I then added a fourth node and resharded to make the slot allocation even:</p>
  
  <pre><code>~ redis-3.2.10/src/redis-trib.rb add-node 127.0.0.1:7003 127.0.0.1:7000
  ~ redis-3.2.10/src/redis-trib.rb reshard --timeout 60000  127.0.0.1:7000
  ...
  How many slots do you want to move (from 1 to 16384)? 4096
  ...
  Source node #1:all
  ...
  redis-3.2.10/src/redis-trib.rb check 127.0.0.1:7000
  &gt;&gt;&gt; Performing Cluster Check (using node 127.0.0.1:7000)
  M: 29fbb7e5f93eac22a224c14d4070139919bb0a5e 127.0.0.1:7000
     slots:1365-5460 (4096 slots) master
     0 additional replica(s)
  M: c90c9f590bb48d328f3eed2fc96af3a7d9cb0f25 127.0.0.1:7003
     slots:0-1364,5461-6826,10923-12287 (4096 slots) master
     0 additional replica(s)
  M: 970b3145574a4f38bbe10548bf6b80f8fdc2854d 127.0.0.1:7001
     slots:6827-10922 (4096 slots) master
     0 additional replica(s)
  M: 2cc0922fcfb3e619b6d733e054dd249a4b6137bf 127.0.0.1:7002
     slots:12288-16383 (4096 slots) master
     0 additional replica(s)
  [OK] All nodes agree about slots configuration.
  &gt;&gt;&gt; Check for open slots...
  &gt;&gt;&gt; Check slots coverage...
  [OK] All 16384 slots covered.
  </code></pre>
  
  <p>Then if you scale back down, reshard the slots back from the :7003 node to the remaining three, you end up with something like:</p>
  
  <pre><code>&gt;&gt;&gt; Performing Cluster Check (using node 127.0.0.1:7000)
  M: 29fbb7e5f93eac22a224c14d4070139919bb0a5e 127.0.0.1:7000
     slots:1365-5460,12288-13652 (5461 slots) master
     0 additional replica(s)
  M: 970b3145574a4f38bbe10548bf6b80f8fdc2854d 127.0.0.1:7001
     slots:0-1364,5461-6826,10923-12287,13653-15017 (5461 slots) master
     0 additional replica(s)
  M: 2cc0922fcfb3e619b6d733e054dd249a4b6137bf 127.0.0.1:7002
     slots:6827-10922,15018-16383 (5462 slots) master
     0 additional replica(s)
  M: c90c9f590bb48d328f3eed2fc96af3a7d9cb0f25 127.0.0.1:7003
     slots: (0 slots) master
     0 additional replica(s)
  [OK] All nodes agree about slots configuration.
  &gt;&gt;&gt; Check for open slots...
  &gt;&gt;&gt; Check slots coverage...
  [OK] All 16384 slots covered.
  </code></pre>
  
  <p>The :7001 node has 4 different groups of hash slots assigned to it. After subsequent resharding this 'fragmentation' of hash slots seems to increase.</p>
  
  <p>Could it ever become a problem (to performance or otherwise) having more and more fragmentation of hash slots?</p>