Upgrading from 8.x to 9.x with _source disabled

Elastic Stack Elasticsearch
1

Hello,

I am exploring disabling _source for some of my indices.

The documentation has warnings about doing that.

One specific line in the warnings is not very clear to me:

"The ability to reindex from one Elasticsearch index to another, either to change mappings or analysis, or to upgrade an index to a new major version."

Does it mean that if I have _source disabled on an index in my ES 8.x cluster, I will not have the ability to upgrade to ES 9.x? Will I have to delete the index before upgrading to ES 9.x?

Thank you

2

Elasticsearch can read indices created in the previous major version so if the index was created in Elsticsearch 8.x you should be able to use this in Elasticsearch 9.x. The issue comes when you in the future move to Elasticsearch 10.x, as this likely will not be able to work with indices created in version 8.x.

4

Thank you.

I still don't get the implication of this phrase though, "or to upgrade an index to a new major version."

5

If you want to upgrade a cluster with indices created in 8.x to 10.x, you will need to reindex these, which is not possible if source is disabled. Also note that disabling source also can affect how you can use these indices in Kibana.

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6

Thanks for the clarification, it will help others if you can update the document to reflect this conversation.

7

There might be a bit more leniency coming there :slight_smile:

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