Elasticsearch data back up and retention


My team is using Camunda 8 self managed on AKS and have the following questions with respect to elasticsearch storage:

Q1. The default PV size is 64Gb in helm installation but got a business requirement to retain the completed process instance data for 8 years. At the moment, we’re not sure how much storage might be required. But I’m interested to know, Can we increase the storage without running helm installation again? Is it possible to auto-scale the storage through some configuration in helm?

Q2. How one can take back up and restore the elasticsearch PVs in Camunda self-managed? I tried to search in the documentation but couldn’t find any.

Appreciate any suggestions or best practices in this area. Thank you in advance.