Understanding nas (network attached storage)

Section 3 – Networked StorageSection 3 – Networked Storage

Introduction

Section Objectives

Upon completion of this section, you will be able to:

Describe the elements, connectivity, and management of: Direct Attached Storage (DAS), Network Attached Storage (NAS), FC and IP Storage Area Networks (SAN), Content Addressed Storage (CAS)

Compare the benefits and challenges of each of the storage models

In this Section …

This section contains the following modules:

1. Direct Attached Storage (DAS)

2. Networked Attached Storage (NAS)

3. Storage Area Networks (SAN)

4. IP Storage Area Networks (IP SAN)

5. Content Addressed Storage (CAS)

Direct Attached Storage (DAS)Direct Attached Storage (DAS)

Module 3.1

Direct Attached Storage (DAS)

After completing this module you will be able to:

Discuss the benefits of DAS based storage strategy

Describe the elements of DAS

Describe the connectivity options for DAS

Discuss DAS management considerations

Identify the best environments for DAS solutions

DAS Benefits

Ideal for local data provisioning

Quick deployment for small environments

Simple to deploy in simple configurations

Reliability

Low capital expense

Low complexity

Physical Elements of DAS

CPU

Motherboard

Clustered group of processors

Processor cards

Complete system

Internal

External

Hard disk(s)

CD-ROM drive

Optical drive

Removable media

Tape devices/tape library

RAID/intelligent array(s)

Portable media drives

Connectivity

Storage

DAS Management: Internal

Host provides:– Disk partitioning (Volume management)

– File system layout

– Data addressing

Direct Attached Storage managed individually through the server and the OS

DAS Management: External

Array based management

Availability – multi-path I/O

Lower TCO for managing data and storage Infrastructure

DAS Performance Considerations

Factors to be considered for DAS performance:

• Hard disks

• Memory cache

• Virtual memory (paging)

• Storage controllers• Protocol supported (e.g. SCSI, FireWire, USB, etc.)

• RAID level

• Bus

Internal DAS Application Example

Hard Drive40 Pin Ribbon Cable

Motherboard

External DAS Application Example

ESCON HBACable for

external DAS connectivity

DAS Challenges

Hosts must be directly connected

Data availability issues–Many single points of failure

Bus, multiple path software, host, application

Data slowdowns possible–CPU congestion, caching, multi-pathing

Volumes are not globally available to all hosts

Scalability concerns

DAS Challenges

Hosts must be directly connected

Data availability

Data slowdowns possible– CPU congestion, caching, multi-pathing

Scalability is limited– Number of connectivity ports to hosts

– Number of addressable disks

– Distance limitations

Downtime required for maintenance

Module Summary

Key points covered in this module:

DAS can be:– An integrated part of the host computer

– Directly connected to a single server

DAS is made up of a CPU, connectivity, and storage devices – There are several options within each of these categories

DAS connectivity uses block-level access protocols

Check Your Knowledge

What are the physical elements of DAS?

Give an example of when DAS is a good solution.

Describe internal DAS connectivity.

Describe external DAS connectivity.

What are some areas that you need to consider as part of DAS management?

Network Attached Storage (NAS)Network Attached Storage (NAS)

Module 3.2

NAS – Network Attached Storage

After completing this module, you will be able to:

Discuss the benefits of NAS based storage strategy

Describe the elements of NAS

Discuss connectivity options for NAS

Discuss NAS management considerations by environment

Identify the best environments for NAS solutions

In this Module …

This module contains the following lessons:

What is NAS?

Managing a NAS Environment

NAS Application Examples

Lesson: What is NAS?

Upon completion of this lesson, you should be able to:

Define NAS and describe its key attributes

List the benefits of NAS

Describe NAS connectivity

NAS Evolution

Network Attached Storage (NAS)

Stand Alone PCNetworked File SharingNetworked PCsPortable Media

for File Sharing

What is NAS?

NAS is shared storage on a network infrastructure. Clients

ApplicationServer

PrintServer NAS Device

NAS Head Storage

General Purpose Servers vs. NAS Devices

Network

Operating System

I/O

File System

Print Drivers

Applications

General Purpose Server(NT or Unix Server)

Network

Operating System

File System

Single Function Device(NAS Server)

Why NAS?

Supports global information access

Improves efficiency

Provides flexibility

Centralizes storage

Simplifies management

Scalability

High availability – through native clustering

Provides security integration to environment (user authentication and authorization)

NAS Device Components

NAS Device

CIFSCIFSNFSNFS

Network InterfaceNetwork Interface

Storage InterfaceStorage Interface

NAS Device OSNAS Device OS

SCSI, FC, or ATA

IP Network

NAS File Services Protocols: NFS and CIFS

NAS Device

Network InterfaceNetwork Interface

Storage InterfaceStorage Interface

NAS Device OSNAS Device OS

SCSI, FC, or ATA

CIFSCIFSNFSNFSIP Network

Windows

Unix

NFS

CIFS

Network File System (NFS)

Client/server application

Uses RPC mechanisms over TCP protocol

Mount points grant access to remote hierarchical file structures for local file system structures

Access to the mount can be controlled by permissions

Common Internet File System (CIFS)

Public version of the Server Message Block (SMB) protocol

Client applications access files on a computer running server applications that accept the SMB protocol

Better control of files than FTP

Potentially better access than Web browsers and HTTP

NAS Physical Elements

Data movers/filers

Management interface– Configure network interfaces

– Create, mount, or export file system

– Install, configure and manage all data movers/filers

– Can be accessed locally or remotely

Connectivity – NAS head to storage

– NAS head to network

Storage

Integrated vs. Gateway NAS

Integrated NAS

NAS Gateway

IP Network

IP NetworkFC Fabric

NAS Head

NAS Head

Integrated NAS System

Integrated NAS System

NAS HeadStorage

Direct AttachIP Network

Gateway NAS System

Clients

Application Servers

Storage

NAS Gateway

FC Switch

IP Network

Lesson Summary

A NAS server is an appliance optimized for file serving functions.

Generally it has a specialized operating system

NAS supports multiple protocols

NAS can be implemented as an integrated system or as a gateway

Fibre Channel Storage Area Networks (SAN)Fibre Channel Storage Area Networks (SAN)

Module 3.3

Fibre Channel Storage Area Networks (SAN)

Upon completion of this module, you will be able to:

Describe the features and benefits of SAN.

Describe the physical and logical elements of SAN.

List common SAN topologies.

Compare and contrast connectivity devices.

Describe connectivity options of SAN.

Describe the I/O flow in the SAN environment.

List SAN management considerations.

Describe applications of a SAN strategy.

In this module …

This module contains the following lessons:

Fibre Channel SAN Overview.

The Components of a SAN.

FC SAN Connectivity.

SAN Management.

SAN Deployment Examples.

Case Study and Applications of FC SAN.

Lesson: Fibre Channel SAN Overview

Upon completion of this lesson, you will be able to:

Define a FC SAN.

Describe the features of FC SAN based storage.

Describe the benefits of an FC SAN based storage strategy.

Business Needs and Technology Challenges

Information when and where the business user needs it

Integrate technology infrastructure with business processes

Flexible, resilient architecture

What is a SAN?

Dedicated storage network

Organized connections among:

Storage

Communication devices

Systems

Secure

Robust.

Evolution of Fibre Channel SAN

SAN IslandsFC

Arbitrated Loop

InterconnectedSANs

FCSwitched Fabric

Enterprise SANs FC Switched Fabric

HUB

Benefits of a SAN

High bandwidth – Fibre Channel

SCSI extension– Block I/O

Resource Consolidation – Centralized storage and management

Scalability– Up to 16 million devices

Secure Access– Isolation and filtering

Lesson Summary

Topics in this lesson included:

Definition of a SAN

Features and Benefits of SANs

Lesson: The Components of a SAN

Upon completion of this lesson, you will be able to:

Describe the elements of a SAN.– Host Bus Adapter (HBA)

– Fiber Cabling

– Fibre Channel Switch /Hub

– Storage Array

– Management System

Components of a Storage Area Network

Host Bus Adapter (HBA)

Fiber Cabling

Fibre Channel Switch /Hub

Storage Array

Management System

HBAHBA

SAN-attached Server

SAN

Nodes, Ports, & Links

Node

HBA

Port 0Port 0

Port 1Port 1

Port nPort n

Link

Port 0Port 0Rx

Tx

HBA

Host Bus Adapters

HBAs perform low-level interface functions automatically to minimize the impact on host processor performance

HBA

Connectivity

Single Mode Fiber

Storage

Multimode Fiber

Host

Connectivity Devices

Basis for SAN communication– Hubs, Switches and Directors

HBA

Storage Resources

Extension of the basic disk drive to an array.– Provides storage consolidation and

centralization

Features of an array– High Availability/Redundancy

– Performance

– Business Continuity

– Multiple host connect

HBA

SAN Management Software

A suite of tools for managing SAN including access of host to storage arrays.

Provides integrated management of SAN environment.

Web based GUI or CLI

Lesson: Summary

Topics in this lesson included:

The elements of a SAN:– Host Bus Adapter (HBA)

– Fiber Cabling

– Fibre Channel Switch /Hub

– Storage Array

– Management System

Lesson: Fibre Channel SAN Connectivity

Upon completion of this lesson, you will be able to:

Describe the Fibre Channel SAN connectivity method and topologies

Describe Fibre Channel devices

Describe Fibre Channel communication protocols

Describe Fibre Channel login procedures

Fibre Channel SAN Connectivity

Core networking principles applied to storage

Servers are attached to 2 distinct networks– Back-end

– Front-end

Users &Application

Clients

Storage & Application

Data

Servers & Applications

SANswitchesdirectors

IPnetwork

What is Fibre Channel?

SAN Transport Protocol– Integrated set of standards (ANSI)

– Encapsulates SCSI

A High Speed Serial Interface– Allows SCSI commands to be transferred over a storage network.

Standard allows for multiple protocols over a single interface.

World Wide Names

Unique 64 bit identifier.

Static to the port.– Used to physically identify a port or node within the SAN.– Similar to NIC MAC address

Additionally, each node is assigned a unique port ID (address) within the SAN– Used to communicate between nodes within the SAN– Similar in functionality to an IP address on a NIC.

World Wide Names: Example

World Wide Name - HBA

1 0 0 0 0 0 0 0 c 9 2 0 d c 4 0Reserved

12 bitsCompany OUI

24 bitsCompany Specific

24 bits

World Wide Name – Array

5 0 0 6 0 1 6 0 0 0 6 0 0 1 B 20101 0000 0000 0110 0000 0001 0110 0000 0000 0000 0110 0000 0000 0001 1011 0010

Company ID24 bits

Port Model seed 32 bits

Fibre Channel Addressing

Fibre Channel addresses are used for transporting frames from source ports to destination ports.

Address assignment method varies with the associated topology (loop vs switch)– Loop – self assigning

– Switch – centralized authority

Certain addresses are reserved – FFFFFC is Name Server

– FFFFFE is Fabric Login

What is a Fabric?

Virtual space used by nodes to communicate with each other once they are joined.

Component identifiers:– Domain ID

– Worldwide Name (WWN)

Fabric

Fibre Channel Topologies

Arbitrated Loop (FC-AL)– Devices attached to a shared

“loop”

– Analogous to Token Ring

Switched Fabric (FC-SW)– All devices connected to a “Fabric

Switch” – Analogous to an IP switch

– Initiators have unique dedicated I/O paths to Targets

Switch

HUB

Switch versus Hub Comparison

Switches (FC-SW)– FC-SW architecture scalable to

millions of connections.

– Bandwidth per device stays constant with increased connectivity.

– Bandwidth is scalable due to dedicated connections.

– Higher availability than hubs.

Hubs (FC-AL)– FC-AL is limited to 127

connections (substantially fewer connections can be implemented for ideal system performance).

– Bandwidth per device diminishes with increased connectivity due to sharing of connections.

– Low cost connection.

Topology: Mesh Fabric

Can be either partial or full mesh

All switches are connected to each other

Host and Storage can be located anywhere in the fabric

Host and Storage can be localized to a single switch

Partial Mesh Full Mesh

Full Mesh Benefits and Tradeoffs

Benefits– All storage/servers are maximum of one ISL hop away.

– Hosts and storage may be located anywhere in the fabric.

– Multiple paths for data using the Fabric Shortest Path First (FSPS) algorithm.

– Fabric management made simpler.

Topology: Simple Core-Edge Fabric

Can be two or three tiers– Single Core Tier– One or two Edge Tiers

In a two tier topology, storage is usually connected to the Core

Benefits– High Availability– Medium Scalability– Medium to maximum

ConnectivityStorage Tier

Host Tier

Core-Edge Benefits

Simplifies propagation of fabric data.– One ISL hop access to all storage in the fabric.

Efficient design based on node type.– Traffic management and predictability.

Easier calculation of ISL loading and traffic patterns.

Lesson: Summary

Topics in this lesson included:

The Fibre Channel SAN connectivity methods and topologies

Fibre Channel devices

Fibre Channel communication protocols

Fibre Channel login procedures

Lesson: SAN Management

Upon completion of this lesson, you will be able to:

Describe SAN management functions– Infrastructure protection

– Provisioning

– Capacity Management

– Performance Management

SAN Management Overview

Infrastructure protection

Fabric Management

Storage Allocation

Capacity Tracking

Performance Management

Infrastructure Security

Physical security– Locked data center

Centralized server and storage infrastructure– Controlled administrator access

Storage Arrays

Switch Switch

Secure VPNor

FirewallServers

Control Station

Corporate LAN

Management LAN (Private)

In-band (FC)

Out-band (IP)

Switch/Fabric Management Tools

Vendor supplied management software– Embedded within the switch

– Graphical User Interface (GUI) or Command Line Interface (CLI)

Functionality– Common functions

Performance monitoringDiscoveryAccess Management (Zoning)

– Different “look and feel” between vendors

Additional third party software add-ons– Enhanced functionality, such as automation

Fabric Management: Zoning

Zoning Components

Zone Zone ZoneZones

(Library)

Zone SetZones Sets(Library)

Members(WWN’s) Member Member Member MemberMember Member

Provisioning: LUN Masking

Restricts volume access to specific hosts and/or host clusters.

Servers can only access the volumes that they are assigned.

Access controlled in the storage and not in the fabric– Makes distributed administration

secure

Tools to manage masking– GUI– Command Line

Capacity Management

Tracking and managing assets – Number of ports assigned

– Storage allocated

Utilization profile– Indicates the percent usage of a given resource over time

– Allows for forecasting

SAN management software provides the tools– Inventory databases

– Report writers

Performance Management

What is it?– Capturing metrics and monitoring trends

– Proactively or Reactively responding

– Planning for future growth

Areas and functions– Host, Fabric and Storage Performance

– Building baselines for the environment

Lesson: Summary

Topics in this lesson included:– Infrastructure protection

– Provisioning

– Capacity Management

– Performance Management

Internet ProtocolStorage Area Networks (IP SAN)

Internet ProtocolStorage Area Networks (IP SAN)

Module 3.4

IP Storage Area Networks

Upon completion of this module, you will be able to:

Describe the benefits of IP SAN.

Describe IP convergence in the SAN and its implications.

Describe and discuss the basic architecture of – FCIP

– iFCP

– iSCSI

Explain potential applications of IP SAN technology.

In this module …

This module contains the following lessons:

IP SAN Overview.

IP SAN Protocols.

Applications of IP SAN.

Lesson: IP SAN Overview

Upon completion of this lesson, you will be able to:

Describe the benefits of IP SAN.

Describe the IP convergence in the SAN and its implications.

List the three common IP SAN approaches.

List the three deployment models (topologies) for IP SAN.

Introduction

Traditional SAN technology is built around Fibre Channel.

IP technology is emerging as an alternative or supplemental transport for storage traffic.

= IP= FC

FCFC IPIP IPIP FCFCIP

FC/IP

FC/IP

FC/IP

FC/IP

IP

IP/ FCIP/ FC

IP/FCIP/FC

Block Storage over IP – Protocol options

iSCSI– SCSI over IP

IP encapsulation done on host / HBA(host bus adapter)

Hardware-based gateway to Fibre Channel storage

FCIP– Fibre Channel-to-IP bridge /

tunnel (pointto point) Fibre Channel end points

iFCP– IP as the inter-switch fabric

Fibre Channel end points

IPIPIP

IPIP FCFC

IP Storage Approaches

iSCSI

FCFC

FC

FC

FC

IPNetwork

IPNetwork

IPNetwork

IPNetwork

iFCPFCIP

iFCP Switch

iFCPSwitch

FCIP Router

FCIP Router iSCSI/FC Gateway

Market Drivers for SAN Internetworking

Fibre Channel SAN challenges.

IP SAN enablers.

Easy to leverage IP equipment and expertise to help manage data in conjunction with Fibre Channel SANs.

Benefits of IP SAN

Cost Effective

Extend the reach of a SAN

IP is Cost Effective

Most organizations already have IP networks and familiarity with traditional network management.

Leverages existing Fibre Channel applications.

Extend the Reach of Your SAN

Standard Fibre Channel Distances.

IP Extends Fibre Channel applications over regional/global distances.

At higher link speeds, IP can handle synchronous applications.

Lesson Summary

Topics in this lesson included:

Describe the benefits of IP SAN.

Describe the IP convergence in the SAN and its implications.

List the three common IP SAN approaches.

List the three deployment models (topologies) for IP SAN.

Lesson: IP SAN Protocols

Upon completion of this lesson, you will be able to:

Describe and discuss the basic architecture of – FCIP

– iFCP

– iSCSI

Fibre Channel over IP - FCIP

Encapsulates FC frames in IP packets.

Creates virtual FC links that connect devices and fabric elements.

Includes security, data integrity, congestion and performance specifications.

IP Datagram

IPHeader

TCPHeader

FCIPHeader IP PayloadIP Payload

Fibre Channel Frame

SO

F FCHeader C

RC

EO

F

SCSI DataSCSI Data

FCIP EncapsulationFCIP Encapsulation

FCIP Benefits

FCIP – Best of both technologies

– Support for existing applications

– Cost effective

– Multi-point networking

Fibre Channel• Widely available• Low latency• High reliability • Off-the-shelf solutions• Mature standards

IP• Widely available• Accepted technology• Trained user base• Affordable• Mature standards

Internet Fibre Channel Protocol - iFCP

Gateway-to-gateway protocol– IP switches & routers replace FC switches

– Transparent to FC drivers

FC transport uses TCP connections– Point-to-multipoint networking possible

IPHeader

TCPHeader

iFCPHeader IP PayloadIP Payload

Fibre Channel Frame

SO

F FCHeader C

RC

EO

F

SCSI DataSCSI Data

iFCP Address Translation &Encapsulation

iFCP Address Translation &Encapsulation

iFCP Benefits

Works with wide range of devices.

Flexible.

Less potential bottlenecking vs. FCIP.

iSCSI

A method to transfer blocks of data using the TCP/IP network.

Serialized service delivery subsystem.

SCSI protocol over IP.

iSCSI Model Layers

IPHeader

TCPHeader

iSCSIHeader IP PayloadIP Payload

SCSI DataSCSI Command Descriptor

SCSI CDB encapsulation

IP Datagram

Storage

Lesson Summary

Topics in this lesson included:

The basic architecture of FCIP.

The basic architecture of iFCP.

The basic architecture of iSCSI.

Content Addressed Storage (CAS)Content Addressed Storage (CAS)

Module 3.5

Content Addressed Storage (CAS)

Upon completion of this module, you will be able to:

Describe the features and benefits of a CAS based storage strategy.

List the physical and logical elements of CAS.

Describe the storage and retrieval process for CAS data objects.

Describe the best environments for CAS solutions.

In this Module …

This module contains the following lessons:

CAS Description and Benefits

Elements of CAS

Data Object Storage and Retrieval

CAS Applications and Case Scenarios

Lesson: CAS Description and Benefits

Upon completion of this lesson, you be able to:

Define CAS.

Describe the key attributes of CAS.

List the features, benefits and drawbacks of CAS.

What is Content Addressed Storage (CAS)?

Object-oriented, location-independent approach to data storage.

Repository for the “Objects”.

Access mechanism to interface with repository.

Globally unique identifiers provide access to objects.

Extensible metadata that enables automated data management practices and applications.

What Is Fixed Content?

Electronic Documents• Contracts, claims, etc.

• E-mail and attachments

• Financial spread sheets

• CAD/CAM designs

• Presentations

Digital Records

• Documents– Checks, securities trades– Historical preservation

• Photographs– Personal / professional

• Geophysical– Seismic, astronomic,

geographic

Digital Assets Retained For Active Reference And ValueDigital Assets Retained For Active Reference And Value

Leverage Historical Value

Improve Service Levels

Generate New Revenues

Rich Media

• Medical– X-rays, MRIs, CTI

• Video– News / media, movies– Security serveillance

• Audio– Voicemail– Radio

Challenges of Storing Fixed Content

Most new digital content is fixed content.

Fixed content is growing at more than 90% annually.

Long-term preservation is required (years-decades).

Simultaneous multi-user access.

Need for faster access to records for business and legal reasons.

Need for location independent data, enabling technology refresh and migration.

Emerging regulations require retention.

Traditional storage methods are inadequate.

Shortcomings of Traditional Storage Options

Tape is slow, and standards are always changing.

Optical is expensive, and requires vast amounts of media in order to store data of any size.

Many times companies retire tape products without warning.

Many times recovering files from tape and optical is time consuming.

Data on tape and optical is subject to media degradation.

Benefits of CAS

Immutability and authentication

Location independence

Single instance storage

Faster record retrieval

Record-level retention,protection and disposition

Technology independence

Online (like Disk)

Optimized TCO

Scalability

Drawbacks of CAS

There are some drawbacks with CAS:

Can be slower than SAN, NAS, or DAS.

Application integration.

Initial cost of ownership is higher even though TCO is significantly lower.

Lesson: Summary

Key points covered in this lesson:

CAS Definition

CAS Description

Benefits and Drawbacks

Lesson: Elements of CAS

Upon completion of this lesson, you will be able to:

Describe the Physical Elements of CAS.

Describe the Logical Elements of CAS.

Storage devices (CAS Based)

Servers (to which storage devices get connected)

Client

Physical Elements of CAS

API

ServerClient CAS-basedStorage

Logical Elements of CAS

The Logical Elements of CAS include the Object-Level Access Protocols.

CAS

API

API

Metadata

39HLTTT2H0404EU6M4A9MUR7TE4

Content Address

Lesson Summary

Key points covered in this lesson:

Physical Elements of CAS

Logical Elements of CAS

Lesson: Data Object Storage and Retrieval

Upon completion of this lesson, you will be able to:

Describe how data gets stored in a CAS environment.

Describe how data is retrieved from a CAS environment.

How CAS Stores a Data Object

API

Application Server

Client

CAS

Object ID

Client presents datato API to be archived

1

Unique ContentAddress is calculated

2

Object is sent to CASvia CAS API over IP

3

CAS authenticates theContent Address and

stores the object

4

Acknowledgementreturned to application

5

Object-ID is retainedand stored for future use

6

How CAS Retrieves a Data Object

Application Server

Client

CAS

Object is needed byan application

1 CAS authenticatesthe request and

delivers the object

4

Application findsContent Address of

object to be retrieved

2 Retrieval request issent to the CAS via

CAS API over IP

3

API

Object ID

Lesson: Summary

Key points covered in this lesson:

How data gets stored in a CAS environment.

How data is retrieved from a CAS environment.