Module 1 Storage Concepts

8/13/2019 Module 1 Storage Concepts

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EMC Induction

Module 1

Storage Concepts


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Objectives

Why do we need a DAS/NAS/SAN solution

Describe a Direct Attach Storage Solution

Describe a Network Attach Storage Solution

Describe a Storage Area Network

Understand the differences between SAN , DAS and NAS

Identify scenarios where each topology would be suited


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Current Situation

Rapid expansion in enterprise storage means we

need well defined strategies

When developing a storage strategy, there are

two main considerations:

The impact of the networking technology on storagearchitecture and content management

The impact of parallel processing on the design of storageproducts


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Why do we need DAS/NAS/SAN solutions?

Rapid growth in required storage for the enterprise

Existing servers do not supply enough local storage

Offload heavy I/O , to a network

Less expensive to buy shared storage than to add to

individual machines

Centralised storage and backup


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Approach

There are three main methods of attaching storage to acomputing infrastructure:

1. Direct Attach Storage (DAS)

2. Network Attach Storage (NAS)

3. Storage Area Network (SAN)


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Direct Attach Storage (DAS)

Cheap

Relatively simple to install

Limited scalability

Each host has dedicated storage attached

directly.

Can be difficult to manage

Many different protocol and interfacestandards developed, leaving vendors to

update definitions as the industry

matured

LAN/WAN

Print Server

Application Server

Database Server

DAS

DAS DAS

SD

PowerEdge2300

!

DAS

DAS DAS

SD

PowerEdge2300

!

DAS

DAS DAS

SD

PowerEdge2300

!

DAS

SD

560/NP

SD

UltraScan

NFS or CFIS clientDAS

SD

560/NP

SD

UltraScan

NFS or CFIS client

DAS

SD

560/NP

SD

UltraScan

NFS or CFIS client


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Network Attached Storage (NAS)

There are two main to access data

across a network: NFS (Network File System)

CIFS (Common Internet File System)

Data is served directly over thenetwork [rather than via applicationserver]

Only as fast as the slowest link on theLAN route

Needs a good LAN infrastructure to already exist

Very easy to deploy - Can be difficult to manage

True file sharing between NFS and CIFS - Linear scalability only


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Storage Area Network (SAN)

Using Fibre Channel switch

fabric technology, SANsprovide:

Easy management throughcentralization

Practically unlimited verticalscalability

Fault tolerance

Efficient use of computerresources


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SAN Characteristics

Connected to a general purpose server, separate from the LANor WAN

Provides shared access to a common storage pool and commonbackup and restore services

Uses a dedicated Fibre Channel network

Reduces the load on the LAN by performing data transfersbetween servers and storage over the SAN

Allows remote location of storage subsystems and tape libraries


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Additional SAN benefits

Exceptional performance

Storage sits on a private Fibre Channel network

May ease LAN traffic by performing server/storage transfers overthe SAN

Shared access to storage pools, backup and restore services

Allows remote location of tape and storage subsystems


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SAN Disadvantages

Very Very expensive.

- e.g. avg switch cost = $15,000

Usually quite complex and difficult to install.

- needs careful planning and documentation of design

Can be a nightmare to manage.

- needs enterprise management software

Can be a nightmare to find and fix problems quickly.

- needs very methodical approach, high SAN knowledge andexperience

Vast combination of designs possible.

Difficult technologies to learn, and gain experience upon.

Upgrades , data migrations and device addition needs careful planning.


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When would we use a SAN?

File and print sharing for

a 50 user network

Application server for

1000+ user network

File and print sharing forup to 250 users

Web Server

Database server forcontact information

Online ordering

application server

DAS or NAS

SAN

NAS

Storage may not be

an issue

DAS

SAN


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Whats the Difference?

SAN NAS

SCSI-block oriented File oriented

Fibre Channel based Ethernet based

Storage server applications

with high performance Fibre

Channel

Usually provided specifically or

general

Client access Client access

Install can be complex Can be installed quickly and

easily


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Lab Exercise DAS/SAN Configurations


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Review

Why do we need a DAS/SAN solution

Describe a Direct Attach Storage Solution

Describe a Storage Area Network

Understand the differences between a SAN and a DAS

Identify scenarios where each topology would be suited

Module 1 Storage Concepts

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