Internet Protocol Storage Area Networks (IP SAN) - pudn.comread.pudn.com/downloads168/ebook/772307/STF3-4IPSAN.pdf · IP Storage Area Networks ... TCP/IP based tunneling/encapsulating

Copyright © 2006 EMC Corporation. Do not Copy - All Rights Reserved.

IP Storage Area Networks (IP SAN) - 1

© 2006 EMC Corporation. All rights reserved.

Internet ProtocolStorage Area Networks (IP SAN)Internet ProtocolStorage Area Networks (IP SAN)

Module 3.4



© 2006 EMC Corporation. All rights reserved. IP Storage Area Networks ( IP SAN) - 2

IP Storage Area NetworksUpon 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.

So far, we have looked at DASNASFC SAN

Now, we will discuss an alternative approach to creating a Fibre Channel SAN using Internet Protocol, or IP SAN.




In this module …

This module contains the following lessons:

IP SAN Overview.

IP SAN Protocols.

Applications of IP SAN.

The lessons in this course will provide an introduction to IP SAN storage and are organized to help meet the module objectives.




Lesson: IP SAN OverviewUpon completion of this lesson, you will be able to:


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.

This lesson provides an overview of IP SAN technology including the benefits and approaches to implementing an IP SAN.




IntroductionTraditional SAN technology is built around Fibre Channel.

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

= IP= FC

Switch

Servers Servers

Servers Servers

Switch

Storage Storage

Traditionally, IP network traffic has been at the file system level. Now, emerging technologies provide for the transfer of block-level data over an existing IP network infrastructure.

IP is being positioned as a storage transport because: IP management is easier. (Note: Many administrators are already familiar with it.)Existing network infrastructure can be leveraged, reducing the cost when compared with an investment in new SAN hardware and software.IP supports multi-vendor interoperability.Many long-distance disaster recovery solutions already leverage IP-based networks.Many robust and mature security options are available for IP networks.




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

“Block storage over IP” represents several different approaches to moving block-level (channel) I/O over IP networks. The three protocols that are gaining most visibility today are iSCSI, FCIP, and iFCP. Each of these protocols leverages IP to extend and add value to the connectivity between hosts and external storage. Following are brief descriptions of each of these protocols.

iSCSI – Host-based encapsulation of SCSI I/O over IP using an Ethernet NIC card. IP traffic routed over network to either a box that extracts the SCSI I/O from the IP packets and sends these on to FC-based external storage, or an iSCSI storage array that handles the conversion and I/O “natively” inside the box.FCIP – Tunneling involving a pair of bridges with Fibre Channel that uses IP as the transport protocol. It is typically used to extend Fibre Channel networks over greater distances and/or over existing IP-based infrastructures.iFCP – Fibre Channel switches that use IP as the inter-switch “fabric” protocol. Again, utilizes existing IP infrastructure (cabling, switches, etc.) to support server-to-storage communications.




IP Storage ApproachesiSCSI

FCFC

FC

FC

FC

IPNetwork

IPNetwork

IPNetwork

IPNetwork

iFCPFCIP

iFCP Switch

iFCPSwitch

FCIP Router

FCIP Router iSCSI/FC Gateway

Servers

Storage

Today, there are three approaches to block storage over IP. They are ordered from top to bottom by commonality with Fibre Channel:

FCIP – TCP/IP based tunneling/encapsulating protocol for connecting/extending Fibre Channel SANs. The entire FC frame is sent over IP links.iFCP – Gateway-to-gateway protocol for FCP over IP. Mapping natively in IP acrossFibre Channel and IP. An IP-based tunneling protocol for interconnecting Fibre Channel devices together in place of Fibre Channel switches. When iFCP creates the IP packets, it inserts information that is readable by network devices and routable within the IP network. iFCP wraps Fibre Channel data in IP packets but maps IP addresses to individual Fibre Channel ports.iSCSI – Native TCP/IP protocol. An IP-based protocol for establishing and managing Connections between IP-based storage devices, hosts, and clients. No Fibre Channel content, but bridging between iSCSI and FC is possible.




IP Storage Deployment Models

= IP= FC

NativeAll Ethernet (No Fibre Channel)iSCSI ProtocolEthernet Switches & Routers

BridgingServers - Ethernet AttachedStorage - FC Attached (SAN or DAS)iSCSI Protocol

ExtensionServers & Storage - SAN AttachedFCIP or iFCP ProtocolSRDF

= IP= FC

= IP= FC= IP= FC

Topologies for IP SAN include:Native – iSCSI allows for all communications using Ethernet. Initiators may be directly attached to iSCSI Targets or may be connected using standard Ethernet routers and switches. Bridging – Architectures allow for the Initiators to exist in an Ethernet environment while the storage remains in a Fibre Channel SAN.Extension – Architectures are most often used to provide connectivity across large distances. Either FCIP or iFCP bring the long distance benefits of IP to Fibre Channel.




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.

Fibre Channel SAN challenges include:High acquisition costSeparate infrastructureSeparate management model

IP SAN enablers include: Availability of Gigabit Ethernet and optical networking productsAvailability of managed Ethernet/IP-based Metro and WAN connectivity servicesIncreased availability of dark fiber and xWDM solutions in the metro

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

IP provides greatest flexibility at lowest cost for latency-tolerant applicationsSuitable for backup across campus network, MAN, or WAN




Benefits of IP SANCost 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.

Most organizations already have IP networks and familiarity with traditional network management. Thus, it is easy to leverage IP equipment and expertise to help manage data in conjunction with Fibre Channel SANs

Leverages existing Fibre Channel applications. This leveraging:Preserves existing Fibre Channel infrastructure and investments.Fully supports Fibre Channel fabric services across the LAN/WAN.Makes the IP Network seem transparent to the FC fabric.




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.

Standard Fibre Channel Distances include:1 Gbps multimode fibre - maximum distance = 500 m1 or 2 Gbps single mode fibre - maximum distance = 10 KmWith DWDM, up to 200 Km

IP Extends Fibre Channel applications over regional/global distancesLAN, MAN, or WAN distancesA typical application includes remote backup and restore.

At higher link speeds, IP can handle synchronous applications such as:Disk mirroringShared storageData sharing




Lesson Summary

Topics in this lesson included:


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.

A SAN is a dedicated storage network that solves many of the complex business data storage needs. IP SAN is a cost effective solution for extending an FC SAN. The three most common approaches to creating an IP SAN are:

FCIPiFCPiSCSI




Lesson: IP SAN Protocols

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

Describe and discuss the basic architecture of – FCIP– iFCP– iSCSI

This lesson describes the three common protocols for IP SAN. It introduces each of the protocols and describes the architectures and technologies for each.




Fibre Channel over IP - FCIPEncapsulates 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

Fibre Channel over IP (FCIP) moves encapsulated Fibre Channel data through a "dumb" tunnel, essentially creating an extended routing system of Fibre Channel switches.




FCIP BenefitsFCIP – 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

The iFCP specification defines iFCP as a gateway-to-gateway protocol for the implementation of a Fibre Channel fabric in which TCP/IP switching and routing elements replace Fibre Channel components.

The protocol enables the attachment of existing FC storage products to an IP network by supporting the fabric services required by such devices.




iFCP Benefits

Works with wide range of devices.

Flexible.

Less potential bottlenecking vs. FCIP.

iFCP works with a wide range of devices.

Flexible and can function as a(n):IP Tunnel for FC-to-FC FCP data transport.Bridge for FC-to-IP FCP data transport.Replacement for FC for IP-to-IP FCP data transport.

iFCP has less potential bottlenecking vs. FCIP since it has a TCP session for every virtual port-to-port connection.




iFCP Maps FCP to an IP Fabric

Device-to-device session

IP Network

iFCP Gateway

iFCP Gateway

FC Switch

FC Loop Disks

iFCP Gateway

iFCP Gateway

FC Tape Library FC Server

iFCP maps Fibre Channel transport services to an IP fabric. In this implementation, gateways are used to connect existing Fibre Channel devices to an IP network and, as such, will include physical interfaces for both Fibre Channel and IP.

iFCP is a TCP/IP protocol that transports encapsulated frame images between gateways. iFCP session end points are Fibre Channel N_Ports.

IP services are in effect for all individual devices and standard IP routing, naming, security, quality of service, and class of service can be used. Device discovery can be automated by standard methods such as SLP (Service Location Protocol), iSNS (Internet Simple Name Service), or can be manually configured.




Addressing and Routing

Local Mode.

Address Transparent Mode.

Routing between gateway regions is IP-only.

Local Mode:Means the Gateway region creates “phantom” FC addresses for foreign nodes.Is more flexible since FC switch domain IDs can be duplicated in each region.

Address Transparent Mode means all gateways share addressing.

Routing between gateway regions is IP-only and FSPF and DFS stay in the region.




iFCP

SAN A SAN B

The two fabrics remain separate

Switch

Servers

Storage

Switch

Storage

ServersGateway Gateway

iFCP allows fabrics to remain independent.

In the example Zoning and Name Server information sharing allows SAN A devices to be visible to SAN B devices and vice versa. Zones are exported from one gateway device to the other.




iSCSI

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

Serialized service delivery subsystem.

SCSI protocol over IP.

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

Serialized service delivery subsystem.

SCSI protocol over IP.TCP is a reliable transport that retransmits dropped packets.IP is an unreliable transport mechanism (packet dropping allowed).Ethernet (10/100/1G/10G) is a popular Physical Transport layer.




iSCSI Model Layers

IPHeader

TCPHeader

iSCSIHeader IP PayloadIP Payload

SCSI Data

SCSI encapsulation

IP Datagram

Storage

The SCSI commands are intercepted by an iSCSI initiator and passed to the TCP stack. Once passed to the TCP stack, the commands are transmitted across the network to a target.

The SCSI commands are exposed once the packet has passed back up the target stack. When the SCSI commands are exposed, the action requested is passed onto the SCSI device for which they were destined. The device performs the requested action.




iSCSI Storage Models

Native

Bridging

= IP= FC

Switch

Servers

StorageGateway

Native All Ethernet (No Fibre Channel)Direct attachedEthernet Switches & Routers

Bridging Servers Ethernet AttachedStorage FC Attached (SAN or DAS)




Controlling IP SANS

Target Z

Initiator BInitiator C

Initiator A

iSNS

IP Network

A

B

CTarget Z - Device A – Initiator A

Target Z - Device B – Initiator B

Target Z - Device C – Initiator C

Due to the shared nature of the connectivity to the storage target, an administrator has two options for connectivity management:

1. Each initiator can be individually configured with a list of its authorized targets and each target can be configured with is list of initiators and access controls

2. An iSNS server can be configured with a list of initiators and targets, which can be done dynamically. Additional information can also be stored such as:

• Discovery Domains which organize the resources into manageable groups• Change State Services which provide notification of storage node change of state

e.g. going off line, domain membership changes, IP link status, etc.• Fibre Channel and iSCSI device mappings.




Internet Storage Name Server OverviewiSNS is a client/server model.

The iSNS server is passive.

iSNS clients register & manipulate the objects in the iSNS server.

An iSNS server can be hosted on a target, initiator, or stand-alone server with a specified IP address.

iSNS is a client/server model

The iSNS server is passive. It ay send state change notifications to the registered clients in response to an action by an iSNS client

iSNS clients register & manipulate the objects in the iSNS server such as:initiatorstargetsmanagement stationsswitches

An iSNS server can be hosted on a target, initiator, or stand-alone server with a specified IP address




iSNS ExampleManagement Platform

iSNS

Device B

Host B

Host A

Host C

Device A

SecurityKeys

Discovery Domains

Storage

Storage




iSCSI Nodes

A single Initiator or Target

Names are assigned to all Nodes

Independent of address

Within iSCSI, a Node is defined as a single Initiator or Target. These definitions map to the traditional SCSI Target/ Initiator model. iSCSI Names are assigned to all Nodes and are independent of their associated address.




Architectural Model

iSCSI NodeTargetIP Network

iSCSI Node

Initiator

Network EntityiSCSI Client

Network EntityiSCSI Server

Network Portal

10.1.2.1TCP port

3260

Network Portal

10.1.2.2TCP port

3260

Network Portal

10.1.1.2

Network Portal

10.1.1.1

There are two major network components associated with iSCSI:The Network Entity, the specific device or gateway accessible to the IP network. The network component is the Network Portal.




FCIP, iFCP and iSCSI Comparison

FC FCIP iFCP iSCSI

Node Discovery Simple Name Service

-

TCP Session Basis - Manual definition of virtual ISL path

Dynamic by node-to-node login

Dynamic by node-to-node login

Intermediate

-

Low

Conversion Overhead

- Low Medium High

Medium

YES

YES

Medium

Simple Name Service

Manual/iSNS/SLP Manual/iSNS/SLP

IP Routable Per Virtual ISL Per Connection Per Connection

Relative Distance Long Unlimited Unlimited

FC Content Full Frames FCP None

Transmitted Overhead

High Medium Medium

Resiliency Low High High

Fabric Contiguity YES NO NO

Port Aggregation YES YES YES

Scalability Low High High

This table is provided as a general, high-level reference to these protocols. It is subject to situation-specific interpretation and is only presented as a learning aid. The fact that many items are not applicable for native FC demonstrates some of the extensibility that IP protocols can add to the SAN.




Lesson Summary


The basic architecture of FCIP.

The basic architecture of iFCP.

The basic architecture of iSCSI.

A SAN is a dedicated storage network that solves many of the complex business data storage needs. IP SAN is a cost effective solution for extending an FC SAN. The three most common approaches to creating an IP SAN are:

FCIPiFCPiSCSI




Lesson: IP SAN Applications

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

Describe common applications of IP SAN technology such as:– Remote Backup and Restore– Remote Data Replication– Storage Consolidation

So far, we have looked at the benefits of an IP SAN and the connectivity methods for implementing and IP SAN. This lesson provides an overview of the common applications for IP SAN technology.

The objectives for this lesson are shown here. Please take a moment to read them.




Remote Backup and Restore

IP Network

FC

FC

FC

Servers

Storage

Disks

Disks

Disks

Server

Server

Customer data can be backed up at an offsite remote data center. This data center may be in the same metropolitan area, or it may be in a separate geographical region.

In case of data loss, backup is accessible directly over the MAN/LAN. A solution such as this could be implemented with either FCIP or iFCP. The IP network cloud could be extended to engulf the FC SANs in the picture using iFCP or iSCSI natively and no FC components would be required.




Remote Data Replication

IP Network

FC

FC

FC

Servers

Storage

Disks

Disks

Disks

Server

Server

Data may be replicated from one site to another across the MAN/LAN. In this application, customer data is kept continuously synchronized across the network. Each site stores live production data. For example, this application could be used to deliver rich media content to distribution centers near users.

Once again, iFCP or FCIP could be used to achieve this as shown. iFCP or iSCSI could perform a similar function if the IP network cloud was extended to encompass the FC SANs shown in the diagram.




Storage Consolidation/Dual Purpose IP Network

IP Network

Servers

Switch

Disks

Disks

Disks

SwitchSwitch

Switch

Disks

Disks

Disks Servers

Servers

Both iFCP and iSCSI can be used to create FC-free SANs. These SANs could be significantly more than what is shown here. As long as response times are within acceptable limits for the applications in question, there is essentially no distance limit for these SANs built on IP technology. Any of the IP switches represented above could be replaced with an iSCSI or iFCP gateway device to allow native FC SAN islands to communicate.




Lesson Summary


Remote backup and restore

Remote data replication

Storage consolidation

An IP SAN can be applied to different storage needs, including:Remote backup and restoreRemote data replicationStorage consolidation




Module Summary

Topics in this module included: :

The benefits of IP SAN.

The IP convergence in the SAN and its implications

The basic architecture of FCIP

The basic architecture of iFCP

The basic architecture of iSCSI

Application of IP SAN technology

In previous modules, we looked at DAS, NAS and FC SAN storage connectivity. This module introduced the Internet Protocol Storage Area Network (IP SAN). We looked at the components and connectivity methods for an IP SAN as well as management topics and applications of IP SAN technology.




Check Your Knowledge

What are the benefits of IP SAN?

What are the three common protocols for IP SAN?

What data storage application could benefit from an IP SAN solution?

Documents

Internet Protocol Storage Area Networks (IP SAN) - pudn.comread.pudn.com/downloads168/ebook/772307/STF3-4IPSAN.pdf · IP Storage Area Networks ... TCP/IP based tunneling/encapsulating