Storage Technologies

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Storage Networking: Fibre, iSCSI, NAS Graeme Holmes Cristie Data Products Ltd

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Agenda EXPERTS IN DATA STORAGE

The Need For SAN Storage Technologies Storage Management

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The Need for SAN

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The Need for SANEXPERTS IN DATA STORAGE Server consolidation Non-disruptive capacity increase More efficient resource utilisation Reduction in hardware/licencing costs Reduced footprint

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Current Situation EXPERTS IN DATA STORAGE Direct Attached Storage Locally attached disk SCSI protocol

Islands of Storage Available storage on server B cannot be utilised by server A

• Limited, disruptive scalability • High Management Costs • Inflexible

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DAS - Scalability

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Limited to the servers predetermined capacity External expansion with SCSI is limited to 15 devices per channel 12M Distance limitation

Expensive, disruptive to scale High management costs Still has over/under utilisation issues

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Centralised storage - NAS

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Network Attached Storage Consolidate File Servers No need to buy servers to add capacity File level storage only Databases require block-level storage Storage traffic moves onto LAN Limited scalability Management

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Centralised Storage - SAN EXPERTS IN DATA STORAGE Dedicated Storage Network optimised for I/O block transfers Centralised storage management Block level storage File & applications

Storage traffic off the LAN Flexible and scalable Any server can have access to any available storage Non-disruptive scalability

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SAN Benefits

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Grows storage independently of servers Centralised high-availability storage reduces storage management overhead Scalable - Supports thousands of interconnected devices High aggregate bandwidth, multiple paths 2Gig, 4Gig fibre, Gigabit Ethernet

Application clustering possible on wider scale Disaster Recovery

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SAN - Disaster Recovery EXPERTS IN DATA STORAGE To assure continued operations, data can be mirrored within the – • same subsystem • to adjacent subsystem • to a subsystem in a remote location

• Storage mirrored or replicated • Block level transfer

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Fibre, iSCSI and NAS

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Fibre Topologies

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Point-to-point Only two FC devices connected directly together No sharing of media - devices each benefit from total link bandwidth

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Fibre Topologies EXPERTS IN DATA STORAGE

Arbitrated Loop 127 addresses or 126 devices per loop Blocking, shared media 100MB/sec speed. Lowest cost Fibre protocol

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Fibre Topologies EXPERTS IN DATA STORAGE

Switched Fabric Connect millions of devices Non-shared media 200MB/sec between nodes

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Other Protocols

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Methods of connecting FC islands FC-IP: Fibre Channel over TCP/IP – tunnelling protocol that encapsulates and transports FC frames over TCP/IP iFCP: Internet Fibre Channel Protocol – allows connection of FC devices over TCP/IP at any distance

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Fibre SAN Management EXPERTS IN DATA STORAGE Heterogeneous Environments, Shared Storage Management Achieved by: • Port Zoning at the switch level • LUN masking within the storage array. Zones prevent devices outside zone from communicating into zone.

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Benefits of Fibre SAN EXPERTS IN DATA STORAGE Massively scaleable High Performance I/O intensive applications Backup

Centralises management of storage

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Considerations

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High hardware and software costs High implementation costs New skills required Distance limitation for Disaster Recovery

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iSCSI A serious alternative?

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iSCSI - What is it?EXPERTS IN DATA STORAGE Final specification approved early 2003 Encapsulates block-level SCSI commands in a TCP/IP frame iSCSI storage NIC connects storage resources over Ethernet A method of creating Storage Networks over IP Two key components Initiator: an iSCSI driver embedded in the server Target: a gateway device that routes data between server & storage

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iSCSI User

1

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User issues a request for data to a local server

2

The SCSI command is encapsulated in TCP/IP & transmitted over IP Network IP Network IP packet

Server

IP packet

iSCSI Initiator Adapter

iSCSI Target Adapter

3

5

The packet is decapsulated separating the SCSI commands

The data request is again encapsulated in TCP/IP 4 then returned

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Storage Device

The SCSI commands are received by the Internal SCSI Controller, and the data is retrieved.

iSCSI Benefits

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Leverages existing investment in technology and skills Relatively low implementation costs Similar speeds to fibre channel 10 Gig Ethernet, 40 Gig announced

No distance limitations

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Considerations

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Relatively new standard Lower performance than FC Perceived as less secure than fibre channel OK for controlled environments IPSec required for large LAN deployments

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TCP Off-load EnginesEXPERTS IN DATA STORAGE iSCSI on standard NIC’s Uses CPU for TCP & iSCSI processing

Software iSCSI with TCP offload TCP processing by TOE card

Hardware iSCSI TCP & iSCSI processing by TOE card

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Off-load Engines

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NAS Where does it fit?

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NAS

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File-based storage architecture Resources attach directly to LAN NAS Headers NAS device which uses portion of SAN storage

File Server, Home Directories, image storage etc File level storage only Databases require block-level storage

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NAS Advantage

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Familiar technology Minimal training

Relatively low-cost way of adding disk space Provides some flexibility Additional units can be easily added

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Fibre or iSCSI?

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Performance vs Cost High performance requirements for business applications – Implement FC + iSCSI

Existing FC SAN costly to expand – Use iSCSI storage to cater for non-intensive applications, migrate from FC to iSCSI

Reduce Storage TCO Implement iSCSI SAN

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Storage virtualisation

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Pooling of disparate systems into single consolidated view – a storage pool Removes LUN limitation and resizing issues Also enables snapshotting, replication etc Re-deploy existing storage arrays

In band – Feature rich Out of band – Out of data path

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Storage Management EXPERTS IN DATA STORAGE

Disparate systems, protocols, vendors leading to Increased management overhead SNIA* developed SMI-S# (Bluefin)

*Storage Networking Industry Association #Storage Management Initiative Specification

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SMI-S - what is it?

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Create common interface enabling software and hardware work together Common Information Mode (CMI) and Web Based Enterprise Management (WBEM) used to describe common storage models and functions Vendors write interfaces to allow their hw/sw to share data Reduction in number of storage management tools required EMC, HP, IBM, CA, HDS backed

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Summary

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Fibre SAN Best performance High cost, new skills

iSCSI SAN Simpler implementation Leverage existing investment in technology and skills

Virtualisation Lower storage TCO Improve data availability

NAS Mixed NAS/SAN environments

Storage Management New standards being developed www.cristie.com

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Thank you

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