When I hit _nodes/stats api and when I see total available free storage space on OpenSearch clusters in cloudwatch metrics i get different results.
According to AWS Documentation
- Operating system reserved space: By default, Linux reserves 5% of the file system for the root user
- OpenSearch Service overhead: OpenSearch Service reserves 20% of the storage space of each instance (up to 20 GiB)
But no explanation is provided in detail about the above overheads.
Precisely, how much space is taken up by these two factors in case of c5.large.search or c6g.large.search
Is there any formula to calculate this?
