r if the master link was disconnected for more than the specified amount of time. For example if the node timeout is set to 5 seconds, and the validity factor is set to 10, a slave disconnected from the master for more than 50 seconds will not try to failover its master. Note that any value different than zero may result in Redis Cluster to be not available after a master failure if there is no slave able to failover it. In that case the cluster will return back available only when the original master rejoins the cluster. cluster-migration-barrier : Minimum number of slaves a master will remain connected with, for another slave to migrate to a master which is no longer covered by any slave. See the appropriate section about replica migration in this tutorial for more information. cluster-require-full-coverage : If this is set to yes, as it is by default, the cluster stops accepting writes if some percentage of the key space is not covered by any node. If the option is set to no, the cluster will still serve queries even if only requests about a subset of keys can be processed.

*Creating and using a Redis Cluster

Note: to deploy a Redis Cluster manually is very important to learn certain operation aspects of it. However if you want to get a cluster up and running ASAP skip this section and the next one and go directly toCreating a Redis Cluster using the create-cluster script.

To create a cluster, the first thing we need is to have a few empty Redis instances running incluster mode. This basically means that clusters are not created using normal Redis instances, but a special mode needs to be configured so that the Redis instance will enable the Cluster specific features and commands.

The following is a minimal Redis cluster configuration file:

port 7000
cluster-enabled yes
cluster-config-file nodes.conf
cluster-node-timeout 5000
appendonly yes

As you can see what enables the cluster mode is simply the cluster-enabled directive. Every instance also contains the path of a file where the configuration for this node is stored, that by default isnodes.conf. This file is never touched by humans, it is simply generated at startup by the Redis Cluster instances, and updated every time it is needed.

Note that the minimal cluster that works as expected requires to contain at least three master nodes. For your first tests it is strongly suggested to start a six nodes cluster with three masters and three slaves.

To do so, enter a new directory, and create the following directories named after the port number of the instance we'll run inside any given directory.

Something like:

mkdir cluster-test
cd cluster-test
mkdir 7000 7001 7002 7003 7004 7005

Create a redis.conf file inside each of the directories, from 7000 to 7005. As a template for your configuration file just use the small example above, but make sure to replace the port number7000 with the right port number according to the directory name.

Now copy your redis-server executable, compiled from the latest sources in the unstable branch at GitHub, into thecluster-test directory, and finally open 6 terminal tabs in your favorite terminal application.

Start every instance like that, one every tab:

cd 7000
../redis-server ./redis.conf

As you can see from the logs of every instance, since no nodes.conf file existed, every node assigns itself a new ID.

[82462] 26 Nov 11:56:55.329 * No cluster configuration found, I'm 97a3a64667477371c4479320d683e4c8db5858b1

This ID will be used forever by this specific instance in order for the instan

redis一个比较大的改变，redis3.0.1稳定版本发布，支持集群。redis集群配置reidsCluster(六)

*Creating and using a Redis Cluster