About the only thing you can say is two specific points: 1. A more resilient node is great, but it in no ways reduces or eliminates the need total nodes. Sometimes nodes become inaccessible due to network outages or system maintenance (e.g., software upgrades), or the vagaries of Java JVM and OOM issues. 2. Replication redundancy is also for supporting higher load, not just availability on node outage.
-- Jack Krupansky From: Jabbar Azam Sent: Friday, November 7, 2014 3:24 PM To: user@cassandra.apache.org Subject: Redundancy inside a cassandra node Hello all, My work will be deploying a cassandra cluster next year. Due to internal wrangling we can't seem to agree on the hardware. The software hasn't been finished, but management are asking for a ballpark figure for the hardware costs. The problem is the IT team are saying the nodes need to have multiple points of redundancy e.g. dual power supplies, dual nics, SSD's configured in raid 10. The software team is saying that due to cassandras resilient nature, due to the way data is distributed and scalability that lots of cheap boes should be used. So they have been taling about self build consumer grade boxes with single nics, PSU's single SSDs etc. Obviously the self build boxes will cost a fraction of the price, but each box is not as resilient as the first option. We don;t use any cloud technologies, so that's out of the question. My question is what do people use in the real world in terms of node resiliancy when running a cassandra cluster? Write now the team is only thinking of hosting cassandra on the nodes. I'll see if I can twist their arms and see the light with Apache Spark. Obviously there are other tiers of servers, but they won't be running cassandra. Thanks Jabbar Azam
