For installations with hundreds of nodes, the number of metrics collected by mongos FTDC can be unworkably large. For example one cluster with ~500 nodes collects ~20k metrics (per sample), mostly due to connPoolStats. This creates problems for downstream consumers of this information, and also will severely limit the retention period for FTDC data.
This is because connPoolStats records several metrics per (pool, host) pair. Some possible solutions
- aggregate the information in some way before recording it to avoid the combinatorial explosion
- remove this information altogether
- add an option to remove it (off by default to avoid catching customers unawares?)