Sardina Openstack Design Guide

Compute

RAM and CPU Load are on this node
RAM count is the total of Compute node RAM, Usable total is 1:1 RAM Over-subscription
CPU count is the total of Compute node CPU, Usable total is 1:2 vCPU Over-subscription
Use 1:1 or 1:2 CPU Over-subs if need high performance Application-CPU intensive application. Or if Container-Kubernates-Openshift on top of it.

Storage

Disk/Volume are on this node
1 Bay : 3-4+ Core, 4+ GB RAM
Default for Initial Cost Effective : 3 Node, 3 Replica, 2n+1, 1 Node Fail Tolerance
Default for Storage Efficient : 5 Node, Erasure Code, 3n+2, 2 Node Fail Tolerance
For Erasure Code, it need at least SATA SSD.
SATA SAS, can use standard replica 3
Use SSD for General Application
Use NVMe for IOPS intensive Application