What is the reason for running Cassandra on Ceph? I have both running in my 
environment but doing different things - Cassandra as transactional store and 
Ceph as block storage for storing files.
________________________________
From: Jan<mailto:cne...@yahoo.com>
Sent: ‎2/‎1/‎2015 2:53 AM
To: user@cassandra.apache.org<mailto:user@cassandra.apache.org>
Subject: Re: Cassandra on Ceph

Colin;
Ceph is a block based storage architecture based on RADOS.    It comes with its 
own replication & rebalancing along with a map of the storage layer.
Some more details & similarities: a)Ceph stores a client’s data as objects 
within storage pools.   (think of C* partitions)b) Using the CRUSH algorithm, 
Ceph calculates which placement group should contain the object, (C* primary 
keys & vnode data distribution) c) and further calculates which Ceph OSD Daemon 
should store the placement group   (C* node locality) d) The CRUSH algorithm 
enables the Ceph Storage Cluster to scale, rebalance, and recover dynamically 
(C* big table storage architecture).
Summary:
C*  comes with everything that Ceph provides (with the exception of block 
storage).      There is no value add that Ceph brings to the table that C* does 
not already provide. I seriously doubt if C* could even work out of the box 
with yet another level of replication & rebalancing.
Hope this helpsJan/
C* Architect




     On Saturday, January 31, 2015 7:28 PM, Colin Taylor 
<colin.tay...@gmail.com> wrote:


 I may be forced to run Cassandra on top of Ceph. Does anyone have experience / 
tips with this. Or alternatively, strong reasons why this won't work.
cheersColin


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