AWS Managed Elasticsearch 6.8 Backup and Restoration

Hi,

Not sure if your question mentioning backup / restore and increase in storage has some corelation; in which case you might want to clarify it further. Hence answering the question about increase in storage:

Increasing storage of elasticsearch cluster would trigger a blue / green deployment[1] which could cause minimal downtime. Also since the number of data nodes are doubled during the activity, it could cause strain on the master nodes since they have more nodes to manage as well as possibly increase search and indexing latency[2]. So you should normally carry out this activity during lean hours.

When you modify the cluster configuration to change the storage, you can run an analysis (shown towards the end of the page) to confirm that the change triggers a blue / green deployment

References:

[1] - https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-configuration-changes.html#bg

[2] - https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-configuration-changes.html#initiate