I run a 10-node Cassandra cluster in production. 99% writes; 1% reads, 0% deletes. The nodes have 32 GB RAM; C* runs with 8 GB heap. Each node has a SDD for commitlog and 2x4 TB spinning disks for data (sstables). The schema uses key caching only. C* version is 2.1.2.
It can be predicted that the cluster will run out of free disk space in not too long. So its storage capacity needs to be increased. The client prefers increasing disk size over adding more nodes. So a plan is to take the 2x4 TB spinning disks in each node and replace by 3x6 TB spinning disks.
- Are there any obvious pitfalls/caveats to be aware of here? Like:
- Can C* handle up to 18 TB data size per node with this amount of RAM?
- Is it feasible to increase the disk size by mounting a new (larger) disk, copy all SS tables to it, and then mount it on the same mount point as the original (smaller) disk (to replace it)?
Thanks in advance.