Hi, Are there any users out there who have Druid data nodes (historical and middle managers) that run on instances that have EBS backed disks. And what kind of BalancerStrategy have they been using?
Since generally the cost of EBS is cheaper than adding a new instance, one of the options that we are exploring internally is to scale up the cluster by dynamically increasing the size of EBS instead of adding new instances. Assuming a homogenous cluster of data nodes, and relatively equal distribution of segments, one naive heuristic would be to increase the EBS volume size by x% on each data node when the overall disk utilization of the cluster goes beyond x%. Currently the config for maxSize of a server is hardcoded in druid.server.maxSize. So we would need to make it dynamically configurable. We would also need to make sure that new instances that come up would be spun up with the updated maxSize. Anyway, I would like to know if the community thinks this a bad idea in general? Are there other ways of scaling up the cluster (assuming cluster CPU utilization is low but disk utilization is high). Is tiering a better option? Thanks, Samarth
