Hey,
I have a few of VM host (bare metal) machines with varying amounts of free hard drive space on them. For simplicity let’s say I have three machine like so: * Machine 1 - Harddrive 1: 150 GB available. * Machine 2: - Harddrive 1: 150 GB available. - Harddrive 2: 150 GB available. * Machine 3. - Harddrive 1: 150 GB available. I am setting up a Cassandra cluster between them and as I see it I have two options: 1. I set up one Cassandra node/VM per bare metal machine. I assign all free hard drive space to each Cassandra node and I balance the cluster using vnodes proportionally to the amount of free hard drive space (CPU/RAM is not going to be a bottle neck here). 2. I set up four VMs, each running a Cassandra node with equal amount of hard drive space and equal amount of vnodes. Machine 2 runs two VMs. General question: Is any of these preferable to the other? I understand 1) yields lower high-availability (since nodes are on the same hardware). Question about alternative 1: With varying vnodes, can I always be sure that replicas are never put on the same virtual machine? Or is varying vnodes really only useful/recommended when migrating from machines with varying hardware (like mentioned in [1])? [1] http://www.datastax.com/dev/blog/virtual-nodes-in-cassandra-1-2 Thanks, Jens ——— Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter
