Cloud storage is a service model in which data is transmitted and stored on remote storage systems, where it is maintained, managed, backed up and made available to users over a network (typically the internet). [Source: TechTarget]

optimized instances are designed for workloads that require high, sequential read and write access to very large

A data set is a collection of related, discrete items of related data that may be accessed individually or in combination or managed as a whole entity. [Source: TechTarget]

on local storage. They are optimized to deliver tens of thousands of low-latency, random I/O operations per second (IOPS) to applications. [Source: AWS]