AWS OpenSearch index lifecycle management

Hi there,

I was trying to google any information about the index lifecycle management in AWS OpenSearch but can't seem to find anything more detailed rather than what is described on this page https://docs.aws.amazon.com/opensearch-service/latest/developerguide/serverless.html - "... takes care of shard and index lifecycle management". It would be great to get more detailed clarification of how index lifecycle management works in OpenSearch serverless.

Essentially I have couple of questions:

1. My use case is about storing application logs in AWS OpenSearch Serverless and I'd like to enforce retention policy so that logs that are older than 30 days are deleted. Is it possible to achieve with OpenSearch Serverless? With managed OpenSearch I would use ISM policy. But the serverless variant of OpenSearch doesn't seem to support ISM.

2. If my collection in OpenSearch serverless gets bigger than 1 TiB what's going to happen? Will it affect applications that are sending data to my OpenSearch collection?

3. Per https://docs.aws.amazon.com/opensearch-service/latest/developerguide/limits.html#limits-serverless the maximum number of indexes within time series collections is 120. In case 121 index is being created will I get an error or some older indexes are deleted automatically?

Thanks a lot in advance!