Knowing when to deploy DAS NAS and SAN can optimize

Availability ScalabilityPerformanceManageabilityCost effectiveness

DAS, NAS, FC-SAN, E-SAN

Coexistent architectures DAS-Based on weak storage industry standards

NAS-Based on strong network industry standards

FC-SAN-SNIA standards will not happen this year

E-SAN - No standards yet and unsolved problems

Appropriate Applications for each Four Choices in NAS

Location of the Network Determines the Architecture

OSI Communication layers

Network Protocols

Frames contain ‘nested’ packets

IP Packets can contain block requests or NFS/CIFS file requests

DAS = Direct Attached Storage

Evolved from the Storage Industry 95% of all storage sold today 7 Major variations of SCSI Many implementations of FC Host file systems request blocks of data

with SCSI or FC commands Data is returned over SCSI buses or FC

loops

DAS Topology

A Performance Critical Customer Reservation System

NAS = Network Attached Storage Based on strong remote file system standards like NFS and

CIFS Uses strong network standards for file requests and data Pioneered by Auspex Predicted by IDC to grow from $1.7 B to $6.6B in three

years or 67% per year. Outboard File System can be Fat or Thin Networks offer security and congestion control unlike FC-

SAN Necessary for NFS/CIFS file sharing

NAS Topology

NAS NFS and CIFS SharingA UNIX-based document control database accessed by NT clients in purchasing

Distributed Storage before NAS Consolidation

Distributed Storage after NAS Consolidation

Technical NAS ApplicationsMCAD, ECAD, software development orgeoseismic applications

Internet Applications Optimized for DAS and NAS

FC-SAN = Fibre Channel SAN SAN means FC-SAN to most folks “Hot” topic - yet misunderstood 7%-10% of shops in production Vision is heterogeneous Reality is homogeneous [proprietary]

EMC = ESN, Compaq=ENSA, HDS=FDN

Security Risks without standards Bottlenecks without standards Heterogeneous switch interoperability is the

main problem today

Heterogeneous FC-SAN Vision

Homogeneous FC-SAN Reality

FC-SAN Link and Node Congestion

Deterrents to FC-SAN today

Source: Computerworld August 7, 2000 - Based on a recent survey of 100 IT professionals aware of FC-SAN first hand.

E-SAN = Ethernet SAN

Where block requests are sent over IP iSCSI proposed by CISCO/IBM to IETP 3ware’s Storage Control Protocol (SCP)

over TCP uses non-SCSI commands SCSI over UDP (SoIP) proposed by Nishan Adaptec is proposing a new transport layer

especially designed for SCSI transport over IP

FC switch vendors fight back by encapsulating FC commands over IP

Cisco and Brocade plan to encapsulate FC over TCP/IP

FCIP is being proposed by Gadzoox and Lucent for long distance WAN / MAN / SAN implementations.

This may lead to FC-SANs interconnected in long distance E-SANs

Why the Fibre Channel people are worried

Summary The location of the network determines the

architecture DAS, FC-SAN, E-SAN = blocks / data NAS = file requests / data Coexistent architectures Only NAS is based on strong network

industry & remote file system standards Only proprietary FC-SANs control the

security risks and bottlenecks of FC E-SAN is emerging with performance and

standards problems to be solved