I am considering building a system as follows:

1.  Data stored in Cassandra
2.  Webservice cluster (stateless) will pull data from cassandra and do 
business 
operations plus security enforcement
3.  Clients will hit the webservice cluster

I'm trying to maintain a low read latency and am worried about the number of 
hops.  Client will hit the webservice.  The webservice will hit a random node 
in 
the cassandra cluster.  The cassandra cluster will then route the the 
appropriate node and the data will flow all the way back.

How many of these hops can I remove?  I would bundle the cassandra and 
webservice processes onto each box.  If I route the webservice to always go to 
the local node, I'll remove one hop.  Is it possible to optimize this further 
so 
that the client can use the cassandra routing logic to go to the webservice 
that 
also houses a cassandra node that contains the data?  In this case, there would 
only be one hop, and if the data is used frequently, I it will likely reside in 
memory without requiring a separate caching layer.  This is an internal 
webservice, so I would be ok with a library on the client side to help with the 
routing.

Is any of this possible?  I was looking at the cassandra apis and couldn't 
figure out a way.

Thanks for any help!



      

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