AWS EC2 Storage Explained

AWS EC2 Storage Types: EBS (Elastic Block Store) vs Instance Store


Think of EBS as a network-attached drive. It’s slower than a local drive (or in AWS parlance, instance storage) but maintains persistence across shutdowns and reboots.

There are two types of EBS: Hard Disk Drive (HDD) and Solid State Drive (SSD).

SSD (Best for Random Access Ops)HDD (Best for Sequential Access Ops)
Provisioned IOPS — Used for I/O-intensive database systems
Throughput Optimized — Big data analysis, data warehousing, log processing

General Purpose — Boot volumes, dev & test systems

Cold — Cold data which requires few scans per day

EBS can be configured as the following volume types:

  • General Purpose SSD (gp2) [default]
  • Provisioned IOPS SSD (io1)
  • Cold HDD (sc1)
  • Throughput Optimized HDD (st1)
  • Magnetic (standard)

Input/output operations per second (IOPS)

Throughput is about the data transfer speed. IOPS refers to the time taken for a storage system to perform an Input or Output operation per second from start to finish.

Root device vs. block devices

Instance Store

An instance store is a physically attached device that loses data each time the instance is rebooted. It’s faster because it’s local as there’s no network latency.