Amazon ElastiCache | Parameter Groups

Question 1

Can nodes of an ElastiCache cluster span multiple subnets?

Parameter Groups

Amazon ElastiCache | Database

Answer 1

Yes, nodes of an Amazon ElastiCache cluster can span multiple subnets as long as the subnets are part of the same Subnet Group that was associated with the ElastiCache Cluster at creation time.

Question 2

What are Parameter Groups? How are they helpful?

Parameter Groups

Amazon ElastiCache | Database

Answer 2

A Parameter Group acts as a “container” for engine configuration values that can be applied to one or more clusters. If you create a cluster without specifying a Parameter Group, a default Parameter Group is used. This default group contains engine defaults and Amazon ElastiCache system defaults optimized for the cluster you are running. However, if you want your cluster to run with your custom-specified engine configuration values, you can simply create a new Parameter Group, modify the desired parameters, and modify the cluster to use the new Parameter Group. Once associated, all clusters that use a particular Parameter Group get all the parameter updates to that Parameter Group. For more information on configuring Parameter Groups, please refer to the Amazon ElastiCache User Guide.

Question 3

How do I choose the right configuration parameters for my Cluster(s)?

Parameter Groups

Amazon ElastiCache | Database

Answer 3

Amazon ElastiCache by default chooses the optimal configuration parameters for your cluster taking into account the Node Type’s memory/compute resource capacity. However, if you want to change them, you can do so using our configuration management APIs. Please note that changing configuration parameters from recommended values can have unintended effects, ranging from degraded performance to system crashes, and should only be attempted by advanced users who wish to assume these risks. For more information on changing parameters, please refer to the Amazon ElastiCache User Guide.