title: Redis Cluster: No automatic failover for master failure
body: <p>I am trying to implement a Redis cluster with 6 machine.
  I have a vagrant cluster of six machines:</p>
  
  <pre><code>192.168.56.101
  192.168.56.102
  192.168.56.103
  192.168.56.104
  192.168.56.105
  192.168.56.106
  </code></pre>
  
  <p>all running redis-server</p>
  
  <p>I edited /etc/redis/redis.conf file of all the above servers adding this</p>
  
  <pre><code>cluster-enabled yes
  cluster-config-file nodes.conf
  cluster-node-timeout 5000
  cluster-slave-validity-factor 0
  appendonly yes
  </code></pre>
  
  <p>I then ran this on one of the six machines;</p>
  
  <pre><code>./redis-trib.rb create --replicas 1 192.168.56.101:6379 192.168.56.102:6379 192.168.56.103:6379 192.168.56.104:6379 192.168.56.105:6379 192.168.56.106:6379
  </code></pre>
  
  <p>A Redis cluster is up and running. I checked manually by setting value in one machine it shows up on other machine.</p>
  
  <pre><code>$ redis-cli -p 6379 cluster nodes
  3c6ffdddfec4e726f29d06a6da550f94d976f859 192.168.56.105:6379 master - 0 1450088598212 5 connected
  47d04bc98ab42fc793f9f382855e5c54ab8f2e20 192.168.56.102:6379 slave caf2cec45114dc8f4cbc6d96c6dbb20b62a39f90 0 1450088598716 7 connected
  040d4bb6a00569fc44eec05440a5fe0796952ccf 192.168.56.101:6379 myself,slave 5318e48e9ef0fc68d2dc723a336b791fc43e23c8 0 0 4 connected
  caf2cec45114dc8f4cbc6d96c6dbb20b62a39f90 192.168.56.104:6379 master - 0 1450088599720 7 connected 0-10922
  d78293d0821de3ab3d2bca82b24525e976e7ab63 192.168.56.106:6379 slave 5318e48e9ef0fc68d2dc723a336b791fc43e23c8 0 1450088599316 8 connected
  5318e48e9ef0fc68d2dc723a336b791fc43e23c8 192.168.56.103:6379 master - 0 1450088599218 8 connected 10923-16383
  </code></pre>
  
  <p>My problem is that when I shutdown or stop redis-server on any one machine which is <code>master</code> the whole cluster goes down, but if all the three slaves die the cluster still works properly.</p>
  
  <p>What should I do so that a slave turns a master if a master fails(Fault tolerance)? </p>
  
  <p>I am under the assumption that redis handles all those things and I need not worry about it after deploying the cluster. Am I right or would I have to do thing myself?</p>
  
  <p>Another question is lets say I have six machine of 16GB RAM. How much total data I would be able to handle on this Redis cluster with three masters and three slaves?</p>
  
  <p>Thank you.</p>