ElasticSearch node and cluster configuration?

Question

Is it better to have two cluster with each have one server with two node and ES_HEAP_SIZE 10g or one server with one node and ES_HEAP_SIZE 20g ?

which of the two following config is better for es i have two dedicated server:

config no1:

          server 1 :
                one cluster : clustername = escluster
                two node    : nodename = **esnode1** **esnode2**
                ES_HEAP_SIZE **10**

           server 2 :
                one cluster : clustername = escluster
                two node    : nodename = **esnode3** **esnode4**
                ES_HEAP_SIZE **10**

config no2:

           server  1  :
                one cluster : clustername = escluster
                two node    : nodename = **esnode1**
                ES_HEAP_SIZE **20**

           server 2 :
                one cluster : clustername = escluster
                one node    : nodename = **esnode2**
                ES_HEAP_SIZE **20**

Answer 1

ES_HEAP_SIZE depends upon the RAM size. Always allocate half of your RAM to ES_HEAP_SIZE with maximum of 32 GB.

For Example: If you have 8GB RAM machine, allocate 4 GB to ES_HEAP_SIZE and Elasticsearch will automatically occupy rest of 4GB RAM. If you have 128 GB machine, allocate 32GB to ES_HEAP_SIZE.

Here is the documentation: https://www.elastic.co/guide/en/elasticsearch/guide/current/heap-sizing.html