Start from 2014 April, Microsoft Azure introduces a new instance tier of Virtual Machine – Basic tier. These instances are well-suited for production applications that do not require the Azure load-balancer (bring-your-own LB or single instance) , development workloads, test servers and memory-focused batch processing applications. 
There are few documents on what is the difference between basic tier VM and standard tier VM so here is a summary note based on my research
Azure price page makes it clear: General purpose compute: Basic tier – An economical option for development workloads, test servers, and other applications that don’t require load balancing, auto-scaling, or memory-intensive virtual machines.
Below are some detail context:
- Availability: Basic tier VM is only available on A0-A4 instances, standard tier VM is available on all size instances
- Disk IOPS: Data disk IOPS for basic tier VM is 300, lower than standard tier VM which has 500 IOPS data disk.
- Price: Single tier VM can have up to 27% less in price than standard tier VM.
- Feature cut: Basic tier VM does not include load balancing or auto-scaling. For basic tier VMs, you can add those to availability set for high availability, and implement your own load-balance mechanisms.
- CPU: Standard tier have better CPU performance than basic tier
Whats the difference in SLA? If Basic is suited for single instance, does that mean there’s no outage downtime?
Single instance instance vm does not have SLA. Only mutiple instance VMs in availability set have.
I have a VM running on Basic Tier A2 now i want to upgrade it to Standarad tier A5.
Do i need to setup all backup endpoint config and all settings again?
Please advise.
Thank you very much ! You have cleared out the difference between them.