What is a storage system

DAS: the starting point

Direct Attached Storage means the computer owns its disks. Inside the chassis or in an external enclosure, either way dedicated to that one machine.

Normal computer parts apply: motherboard, CPU, RAM, NIC, disk, OS, apps.

SAN and NAS storage systems

Shared, centralized storage that many devices reach over a network.

SAN vs NAS is about the access type and protocols used to get at the storage, not the box itself. Details in comparing SAN and NAS.

Inside a storage system

Same anatomy as a server, renamed:

• The motherboard, CPU, and RAM become the controller.
• The disks become the disk subsystem.
• The software is the storage OS (NetApp, Dell EMC, HPE, Hitachi, Pure, IBM, Oracle, Nutanix…).

It scales from a 2U box with a couple dozen drives to multi-rack systems.