EBS Performane Tuning

AMI - Template required to launch an instance. Includes customization done on top of base AMI.
Virtualisation: -HVM Hardware assisted VM. AWS  Advised to use this though supports both.
                        -Para Virtualisation
Hypervisor keeps instances separated running on same physical m/c.
Hypervisor  keeps Instances pyhiscal network interface and virtual network interface separated using firewall
You can select AMI with EBS or instance store as root device type. AMI is cretaed from Instance.

EBS can be attched or detached but ephenrmal storage/instance store can't be done so.
AMI convention:
General purpose - T
Compute optimized - C
Memory optimized - X
Accelerated Programming- P
Storage optimized- H
Instance store:
EBS optimized: better perofmance with  additional dedicated throughputs for EBS input/output

More IOPS : SSD based drive
  Genral 3 IOPs/Gib
  Provisioned: more than 100 to 32000  IOPS,
More throughputs required :  HDD based drive. Infrequently used.
     - Throughput optimaised HDD: Throughput intensive workload. Anohter type is cold HDD.
     - Cannot be used as root volume of the Ec2 instance.
Volume
- Root volume cannot be detached.
- Volume and the instances need to be in the same AZ.
- We can have many voume attached to one instance but cannot have many instances attahced to one volume.
- Volume can be upgraded without affecting instances.
AMIs are region specific.
EBS Volume types can be changed at run time without terminating instaces.
EBS volume and instances must be in the same availability zone.

Encryption:
- Uses 256-bit AES alogorithm.
- Uses KMS master key to encrypt the volume and snapshot created from those.
Snapshots:
- Point in time backup data of a EBS volume. Incremental backup.
- Volume created from replciated snaphot loaded lazily.
- Snapshot  is regin specific and supports cross region copy.
- Snapshots are incremental volume and stored in S3.

EBS Volume Performance :
- Use EBS optimized instance.
- Modern Linux Kernel.
-Use RAID 0 to Maximize Utilization of Instance Resource

AWS Cloudwatch Metrics for EBS:
- Provide Volume status check.

Raid 0: Increase Performance
Raid 1: Increase Fault Tolerance