This would give insight into basic questions like "write rate to redis in ops/sec or bytes/sec" and "what are the main use cases". The lack of information is an obstacle to alternative store and multi-DC discussions (e.g. main stash migration work).
We'd have to exclude or have logic to handle WAN cache key prefixes.
- Have gauge metrics in Grafana for bytes written from Memcached via BagOStuff, by keygroup level (including WANObjectCache).
- Have gauge metrics in Grafana for bytes read from Memcached via BagOStuff, by keygroup level (including WANObjectCache).).
See T254608 for the WANObjectCache-specific version of this (might be inspiration and/or become obsolete).