ES5.5.0 cluster construction optimization points

1. How to decide how many data nodes to deploy?
   Based on the following principles:

   • No more than 3 index shards on a single node
   • The data volume of each shard does not exceed 30G.
     If the data volume of a single index is too large and the node resources are insufficient, consider splitting the index

2. How to query faster?
   Routing. Combining business and routing query can greatly improve query speed.

3. The system configuration of the host where the node is located

   • Maximum number of open files
     Modify the /etc/security/limits.conf file and add or modify the following line: (Please switch to the root user and force the file to be modified)
     * hard nofile 65536

     * soft nofile 65536
     

   • Virtual memory
     sysctl -w vm.max_map_count=262144

   • Maximum lock memory address space
     Modify /etc/security/limits.conf, add the following content in limits.conf
     * soft memlock unlimited

     * hard memlock unlimited
     

4. elasticsearch.yml
   locks the memory and does not use the swap area swap
   bootstrap.memory_lock: true