Ref: https://learn.cantrill.io/courses/1820301/lectures/41301319

• Summary
• Contents:

Storage Types

By Location

• Local storage = Directly-attached storage
  • 👍 Super fast (directly attached to HW)
  • e.g.: in Amazon EC2, Instance Store volumes are local storage (inside EC2 host)
  • 👎 Problem: storage lost if
    • Disk failure
    • HW failure
    • EC2 instance moves to another host
• Network storage
  • Network-Attached Storage (NAS) ≈ Storage Area Network (SAN)
    • 💡 NAS is usually one simple device, whereas SAN is a cluster of devices
  • Storage volumes delivered over the NW
    • On-premise environments use fiber channel or protocols like iSCSI
    • Amazon EC2 uses Amazon EBS (Elastic Block Store)
  • Separate from HW → highly resilient
    • 👍 Storage can survive issues with EC2 host
    • 👍 Storage can be easily moved between systems

By Persistence

• Ephemeral storage = Temporary storage
  • e.g. RAM memories, in-memory caches…
  • Amazon EC2 uses Instance Store → doesn't persist long-term
• Persistent storage = Permanent storage
  • e.g. Hard-Disk Drive (HDD), Solid-State Drive (SSD)…
  • Amazon EC2 uses EBS volumes → they can live past the lifetime of an EC2 instance

Storage Categories (Available in AWS)

• Categories define how storage is presented & what it can be used for

Block Storage

• 🔧 Collection of addressable blocks → cubes with #

• Presented to OS as:

  • Blank physical hard drive
    • e.g. spinning hard disk, SSD…
  • Logical volume (maps to physical storage)
    • e.g. EBS volume

• No built-in structure provided
  • Mountable
    • OS can put a file system (FS) on top of it → e.g. NTFS, ext3…
    • OS can mount on C:/ (Windows) or / (Linux root volume)
  • Bootable
    • most EC2 instances use an EBS volume to boot their OS
• NW-attached storage systems provide block storage over NW
• 👍 Advantage: high performance storage within an OS