How to calculate the hit ratio?

[rlolima]

Hi all,

MongoDB has no metric for the pages hit, so the exporter doesn't have it either. I am trying to devise a logic to get, at least, a close hit ratio. I am thinking about something like that below, and I would like to have some help from the community, if possible. :)

(mongodb_mongod_wiredtiger_cache_pages_total{} - mongodb_mongod_wiredtiger_cache_evicted_total{type="unmodified"}) / mongodb_mongod_wiredtiger_cache_pages_total{} * 100

mongodb_mongod_wiredtiger_cache_pages_total{} - mongodb_mongod_wiredtiger_cache_evicted_total{type="unmodified"} would be the hit part.

What do you think?

Thx in advance,