Updated Filer (markdown)

Filer.md

@@ -12,6 +12,10 @@ The default backend, LevelDB, is for simple, non-distributed single nodes.
 
 The other backends, Redis and Cassandra, are for clustering backing stores that can be distributed across several nodes at high scale.
 
+The LevelDB backend is very capable and efficient; the main disadvantage it has, relative to the distributed backends, is that it presents a single point of failure. In "[pets vs. cattle][pvc]" terms, the LevelDB backend is only suitable for "pet" servers, while the Redis and Cassandra backends are suitable for "cattle" servers.
+
+[pvc]: https://blog.engineyard.com/2014/pets-vs-cattle
+
 ## Initialization
 
 The LevelDB and Redis backends need no initialization.