To size your SAP h[y]bris platform for production you need to gather key metrics :
- total number of products and price rows
- total number of expected carts and orders
- number of back office users
- level of cache (static and non-static resources)
- expected number of concurrent users
Following are example of sizings, they would probably not fit exactly your needs but can help guide in your approach :
Minimum
50 concurrent users (BO users and operations have an impact on the store)
This is the minimum platform sizing you should start with for production (SAP Hybris 5.5+), it has the minimum key features of a modern platform :
- Load balancing
- Cloud provider load balancer (Amazon big IP, Azure cloud services,….)
- Database load balancing with HA proxy
- Fail over (one application server and one db server could be down, the platform is still up)
- Disaster recovery (each nodes could be easily replaced from a template if corrupted)
- Sessions are sticky

Medium
50 – 100 concurrent users
This medium size SAP Hybris platform has the same features than the minimum one plus :
- SOLR cluster
- Dedicated back office server (dedicated for conjobs as well)

Large
100 – 200 concurrent users
This large size Hybris platform has the same features than the medium one plus :
- Dedicated web servers for static content (Apache + Mod JK)

X-Large
200 – 500 concurrent users
This X-Large size SAP Hybris platform has the same features than the large one plus :
- Web servers are caching content (Varnish)
- SAP Hybris cluster size increased from 3 to 5 vms

Extreme
over 500 concurrent users
This medium size SAP Hybris platform has the same features than the large one plus :
- Dedicated Memcached cluster for session share between Tomcat instances
