AWS Pricing Solution

EC2 are like virtual machines

DB require more RAM
Analytic requires more CPU
Compute optimised for more CPU'

GPU instances are for graphics

Memory optimised --> More memory ,suit for DB related stuff'

Switching will have a down time but no data loss

Autoscaling or putting behind load balancer will be an option to avoid any downtime.

T2 micro is the only server available in free trier .

Pricing
https://aws.amazon.com/ec2/pricing/

Reserved Instances:
1. Some long term commitment, the discount can be up to 75%. Only thing is I will have to use for 1 or 3 year term to reduce their total computing costs.
.2. Do I need to use for 1 week or 1 month or 1 year? Based on that we can save the costing.

The Reserve instances would be available either for 1 year for 3 years.

eg. 4 hours usage- On-demand. If I need a server 24*7 for 1 year - Reserved Instances. Save 75

24*7 for 14 months. 1 year : reserved instances + 2 months on -demand instances

Need Server 3 hours per day for 12 months
RI= 10130
OD= 2*3*365= 2190 OD is better

Spot Instances:
Up to 90 percent. Servers are not guaranteed to be available. Not good for mission critical services. Amazon can take it back from the spare capacity and can use it to  sale on the basis of RI or On-demand Instance.
Amazon will  not give nay notice hence the server will disappear all of a sudden.

When to use:
1. When we do not have mission critical application to be deployed
2. Use in cluster setup. Master RI, Client : RI . Both should be up and runing.
Other client instances can be on spot instances Even if one of the node goes down, it will not have impact.We can have add many spot instances.
Mitigating the risk by using 2 RIs and then spot instances.
Data would be stored in shared disk, so the data is not lost .
Data warehousing solution can also use spot instances,