Hi Mike van Lienden,
Thank you for reaching out to Microsoft QA. The Memory Optimized Eadsv5 Series Compute you see in the reservation portal is indeed the underlying hardware for the Business Critical Eadsv5 tier available for MySQL Flexible Server. Even though the names do not match exactly due to recent updates in Azure’s compute tier structure, purchasing a reservation for Memory Optimized Eadsv5 will correctly apply to your "Business Critical Eadsv5" deployment.
If Azure Advisor does not show a recommendation, this is typically because there is not yet enough usage history or a significant projected saving to suggest a reservation. As you use your server more over time, Advisor may recommend a reservation when it identifies a cost-saving opportunity.
1."Memory Optimized Eadsv5" reservations are valid and will apply to "Business Critical Eadsv5" flexible servers.
2.The naming difference is due to ongoing Azure portal updates; it does not impact your billing or reservation usage.
3.Advisor recommendations depend on sufficient and consistent server usage data.
Helpful References:
1.https://learn.microsoft.com/en-us/answers/questions/5619123/azure-database-for-mysql-reservation-sku-naming-in
2.https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concepts-azure-advisor-recommendations
3.https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concept-reserved-pricing
4.https://learn.microsoft.com/en-us/azure/mysql/flexible-server/concepts-service-tiers-storage
Hope this helps. Do let us know if you have any further queries.