What is the data problem that you are trying to solve with Cassandra? Is it high availability? Low latency queries? Large data volumes? High concurrent users? I would design the solution to fit the problem(s) you are solving.
For example, if high availability is the goal, I would be very cautious about 2 nodes/machine. If you need the full amount of the disk – you *can* have larger nodes than 1 TB. I agree that administration tasks (like adding/removing nodes, etc.) are more painful with large nodes – but not impossible. For large amounts of data, I like nodes that have about 2.5 – 3 TB of usable SSD disk. It is possible that your nodes might be under-utilized, especially at first. But if the hardware is already available, you have to use what you have. We have done multiple nodes on single physical hardware, but they were two separate clusters (for the same application). In that case, we had a different install location and different ports for one of the clusters. Sean Durity From: William R <tri...@protonmail.com.INVALID> Sent: Thursday, April 18, 2019 9:14 AM To: user@cassandra.apache.org Subject: [EXTERNAL] multiple Cassandra instances per server, possible? Hi all, In our small company we have 10 nodes of (2 x 3 TB HD) 6 TB each, 128 GB ram and 64 cores and we are thinking to use them as Cassandra nodes. From what I am reading around, the community recommends that every node should not keep more than 1 TB data so in this case I am wondering if it is possible to install 2 instances per node using docker so each docker instance can write to its own physical disk and utilise more efficiently the rest hardware (CPU & RAM). I understand with this setup there is the danger of creating a single point of failure for 2 Cassandra nodes but except that do you think that is a possible setup to start with the cluster? Except the docker solution do you recommend any other way to split the physical node to 2 instances? (VMWare? or even maybe 2 separate installations of Cassandra? ) Eventually we are aiming in a cluster consisted of 2 DCs with 10 nodes each (5 baremetal nodes with 2 Cassandra instances) Probably later when we will start introducing more nodes to the cluster we can decommissioning the "double-instaned" ones and aim for a more homogeneous solution.. Thank you, Wil ________________________________ The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to our clients any opinions or advice contained in this Email are subject to the terms and conditions expressed in any applicable governing The Home Depot terms of business or client engagement letter. The Home Depot disclaims all responsibility and liability for the accuracy and content of this attachment and for any damages or losses arising from any inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other items of a destructive nature, which may be contained in this attachment and shall not be liable for direct, indirect, consequential or special damages in connection with this e-mail message or its attachment.
