what is a good AWS instance type for a coreos etcd cluster

[Norman Khine]

i am trying to set a production 5 node coreos cluster and wanted to know what is a recommended instance type that i should use? currently i am using c4.large

any advise much appreciated

[Rob Szumski]

That should be good. The two main things to think about are:

1. etcd stores keys in RAM (and snapshots to disk), so you need enough of that for your data set
2. etcd doesn’t serve a successful write until it is written to disk on a quorum of machines, which means it is IOP-sensitive. Larger instances generally get more IOPs. SSDs will help here too.

- Rob