CODEWITHSUNDEEP
elasticsearchlucene
Devasish
Devasish

Reputation: 1957

When should I move to multinode elasticsearch cluster?

I have a node with 32GB Memory and Quad Core 3.2GZ CPU. I am using single node ElasticSearch6.2.1 (ES) cluster and assinged 16GB Memory to ES. I am using ES for my catalog search. It's working fine but sometimes (2-3 times a month) ES is getting overwhelmed a too slow to respond and CPU utilization is becoming 100% (ES using the major part) at that time and until I restart ElasticSearch it does not respond.

I have checked all my queries and they are okay. In my single node cluster there are 14 indices with an average 50,000 document.

I need to know should I add an extra node in my cluster?

Also my curiosity is:- Is there any parameter like index size, traffic to ES etc. by observing which I should decide on adding a new node?

My generalized question is :- When Should I move to multi-node Elasticsearch cluster?

Upvotes: 0

Views: 53

Answers (1)

Christophe
Christophe

Reputation: 2200

If you have a single node it's not really a cluster it's just a single node.

  • First your performances issues could be generated because of many problems : high memory, too many requests ... I would advise you to try to evaluate first the number of requests that you have when there is a high load (netstat on the machine) and to check whether the allocated memory is consumed in the JVM or not (use jconsole or watch at logs). Watch also your mappings for full text search (text fields on suggest), this could use a big amount of memory. If you think that the issue is related to the number of connections you should definitely have a multi node cluster configuration. If the issue is related to memory either you'll have to tune your mappings or increase the memory allocated rather than just adding nodes.
  • Second concerning your cluster, to my mind you should at least have 2 servers. This is for redundancy. This will prevent most of your loss of service issues if one server doesn't answer anymore. You should not wait to scale your cluster. Put also a regular check to see if the service is still up on one machine and if not either restart automatically your service or send one emails so that you'll be able to restart manually.

Upvotes: 1

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