I'm trying to determine a node configuration for Cassandra. From what I've been able to determine from reading around:
1. we need to cap data size at 50% of total node storage capacity for compaction 2. with RF=3, that means that I need to effectively assume that I have 1/6th of total storage capacity. 3. SSDs are preferred, but of course reduce storage capacity 4. using standard storage means you bump up your RAM to keep as much in memory as possible. Right now we are looking at storage requirements of 42 – 60TB, assuming a baseline of 3TB/day and expiring data after 14-20 days (depending on use case), I would assume based on above that we need 252- 360TB total storage max. My questions: 1. is 8TB (meaning 1.33 actual TB storage/node) a reasonable per node storage size for Cassandra? I don’t want to use SSDs due to reduced storage capacity -- I don't want to buy 100s of nodes to support that reduced storage capacity of SSDs. Given that I will be using standard drives, what is a reasonable/effective per node storage capacity? 2. other than splitting the commit log onto a separate drive, is there any other drive allocation I should be doing? 3. Assuming I'm not using SSDs, what would be a good memory size for a node? I've heard anything from 32-48 GB, but need more guidance. Anything else that anyone has run into? What are common configurations being used by others? Thanks in advance, -- Arun
