And I agree it is an advantage that at least in this scenario no reboot is needed, for instance if you plan to upgrnde MongoDB version. Actually when you can plan the downtime it is usually simpler to handle in the general case of many cache hosts running at the same time when you can do the upgrade incrementally, but it is nice that a single big server can be upgraded without the problem of the cache reheating.
Apologizes again for not reading the article with more care.
For example, at Google my caching strategies could be exported in production with only a few minor changes to the code. If we experienced data center downtime I could actually offload a hot cache to the other backing stores in round-robin configuration. The problem isn't when one database server gets taken down, it's when all the servers in the datacenter get taken down at once without any warning.