anchor.diff:  # enable or disable keepalive on rpc connections
   rpc_keepalive: true
   
  -# Cassandra provides three options for the RPC Server:
  -#
  -# sync  -> One connection per thread in the rpc pool (see below).
  -#          For a very large number of clients, memory will be your limiting
  -#          factor; on a 64 bit JVM, 128KB is the minimum stack size per thread.
  -#          Connection pooling is very, very strongly recommended.
  -#
  -# async -> Nonblocking server implementation with one thread to serve 
  -#          rpc connections.  This is not recommended for high throughput use
  -#          cases. Async has been tested to be about 50% slower than sync
  -#          or hsha and is deprecated: it will be removed in the next major release.
  -#
  -# hsha  -> Stands for "half synchronous, half asynchronous." The rpc thread pool 
  -#          (see below) is used to manage requests, but the threads are multiplexed
  -#          across the different clients.
  +# Cassandra provides three out-of-the-box options for the RPC Server:
  +#
  +# sync  -> One thread per thrift connection. For a very large number of clients, memory
  +#          will be your limiting factor. On a 64 bit JVM, 128KB is the minimum stack size
  +#          per thread, and that will correspond to your use of virtual memory (but physical memory
  +#          may be limited depending on use of stack space).
  +#
  +# hsha  -> Stands for "half synchronous, half asynchronous." All thrift clients are handled
  +#          asynchronously using a small number of threads that does not vary with the amount
  +#          of thrift clients (and thus scales well to many clients). The rpc requests are still
  +#          synchronous (one thread per active request).
   #
   # The default is sync because on Windows hsha is about 30% slower.  On Linux,
   # sync/hsha performance is about the same, with hsha of course using less memory.
  +#
  +# Alternatively,  can provide your own RPC server by providing the fully-qualified class name
  +# of an o.a.c.t.TServerFactory that can create an instance of it.
   rpc_server_type: sync
   
  -# Uncomment rpc_min|max|thread to set request pool size.
  -# You would primarily set max for the sync server to safeguard against
  -# misbehaved clients; if you do hit the max, Cassandra will block until one
  -# disconnects before accepting more.  The defaults for sync are min of 16 and max
  -# unlimited.
  -# 
  -# For the Hsha server, the min and max both default to quadruple the number of
  -# CPU cores.
  -#
  -# This configuration is ignored by the async server.
  +# Uncomment rpc_min|max_thread to set request pool size limits.
  +#
  +# Regardless of your choice of RPC server (see above), the number of maximum requests in the
  +# RPC thread pool dictates how many concurrent requests are possible (but if you are using the sync
  +# RPC server, it also dictates the number of clients that can be connected at all).
  +#
  +# The default is unlimited and thus provide no protection against clients overwhelming the server. You are
  +# encouraged to set a maximum that makes sense for you in production, but do keep in mind that
  +# rpc_max_threads represents the maximum number of client requests this server may execute concurrently.
   #
   # rpc_min_threads: 16
   # rpc_max_threads: 2048
  
positive.code: 
  # emergency pressure valve: each time heap usage after a full (CMS)
  # garbage collection is above this fraction of the max, Cassandra will
  # flush the largest memtables.  
  #
  # Set to 1.0 to disable.  Setting this lower than
  # CMSInitiatingOccupancyFraction is not likely to be useful.
  
negative.code: # NoScheduler - Has no options
  # RoundRobin
  #  - throttle_limit -- The throttle_limit is the number of in-flight
  #                      requests per client.  Requests beyond
  #                      that limit are queued up until
  #                      running requests can complete.
  #                      The value of 80 here is twice the number of
  