Elastic Block Storage

• This is the storage service which provides virtual disks to virtual machines (ec2 instances) in AWS.
• Scope of EBS is Availability Zone. EBS can be mounted to an EC2 instance running in same AZ.
• EC2 instance and EBS will be alloacated in the same AZ but on different physical servers. Even after ec2 instance is deleted we can still have virtual disk (EBS Volume)
• When we shutdown ec2
  • There are no charges for ec2
  • charges continue for ebs
• The virtual disk is called as EBS volume and the backup of EBS volume is called as EBS snapshot.
• EBS volume has a lifetime independent of ec2 instance as it is alloacted from a different physical server.
• In AWS it is mandatory that the os disks has to be EBS volume
• EC2 instance will be charged based on number of running hours
  
• EBS is charged as long as disk is present in AWS
  
  
  
• EC2 instance can be mounted with multiple volumes (Empty Volumes)
  • while creation => AWS will create filesystems
  • Post creation of EC2 => We need to create filesystem
• The other volume in AWS is Instance store volume.
• Instance store volume cannot be used as root/os disk. Instance store volume is created from same physical server where your ec2 instance gets created. When you stop the ec2 data is lost.
• Not all instance types support instance store
• EBS volume Types: EBS volume types are categorized by Disk types
  • SSD:
    • General Purpose
    • Provisioned IOPS
  • HDD:
    • Cold
    • Throughput Optmized
  • Magnetic