Storage Networking Architectures
Direct-Attached Storage
What is
Direct-Attached Storage (DAS)?
• Traditional way of implementing storage
• Storage is managed by a single host
• Other hosts must access the storage through
that single host, over the LAN
Direct-attached
external storage
Fibre Channel
SCSI
Tape Device
Direct-attached
internal storage
Direct-attached
external storage
Direct-attach storage (DAS):
DAS is the traditional storage architecture in which storage devices are
directly attached to a server’s I/O bus.
It uses a Block I/O architecture.
Storage devices can be internal disks or external disk subsystems,
typically attached to a SCSI bus.
Storage sits “behind” the server; other hosts must access storage
resources over the LAN.
DAS Storage that is accessible by or through an individual server
Storage is captive to that server
spare capacity could not be allocated to another server