View content of memcached

1. As a general rule, it's normally expected that you just accept that the cache may or may not have what you want.
   • It depends on the scenario, but it sounds like you might benefit from a higher one. There's no great loss having it higher (2-5 minutes).
   • Yes. Memcache will usually cache the values again on Server 2 (after fetching from the DB because Server 1's cache is unavailable).

You probably also lower your TCP timeout being used to reconnect to the possibly-dead server.

Memcached could leak memory (these things happen), but it'd show up in the memory accounting. Absent a fairly unlikely kernel bug, memory accounting will be accurate. The long and the short of it is that you're missing something in your diagnostic actvities. Collect more data and keep staring at it.