Storage Note 6 SAN

SAN（Storage Area Networks）

1. SAN advantage benefits
2. SAN components components
3. SAN connection optionsconnective options
4. FC protocol FC addressing protocol addressing\
5. FC topology topologie

Advantages and disadvantages of SAN

fiber channel fiber channel

SAN components

FC three kinds of interconnection

FC port type
fabric

Business Needs and Technological Challenges - Feelings Are Not the Point

1. real-time information just-in-time info
2. information infrastructure, business integration integration of info infrastructure with business processes
3. Flexible flexible flexible resilient

DAS is inefficient for the above processing

What is SAN

1. Dedicated high speed network of servers and shared storage devices
2. block level data access block level data access
3. Resource integrationresorce consolidation
   1. centralizedd storage, management
4. Scalability
   1. Theoretical limit 15 million devices
5. secure access secure access

Understanding fibre channel

1. high-speed network technology
   1. Optical fiber cables Front connection
   2. Serial copper cables Serial copper cables (back end)
      The latest FC achieves 16Gb/s

The server is connected to 2 different networks

• front end
• Back-end
  Users and application clients connect to Servers and applications through IP network, and then connect to storage and application data through FC SAN

FC SAN Evolution (see p8 for details)

1. SAN Islands FC Arbitrated Loop
2. Interconnected SANs FC Switched Fabric Interconnected SAN FC Switched Fabric
   1. Note that switched fabric is the original fabric of the exchange structure fabric
3. Enterprise SANs FC Switched Fab Enterprise SAN FC Switched Fab

Components of SAN

Node ports

example

• hosts
• storage
• tape library

ports are available in

1. Host HBAs
2. front-end adapter in storage
3. transmit Tx link and receive Rx link in each port

HBA automatically executes low-level interface functions low-level interface functions automatically , minimizing the impact of minimize impact on performance on host performance

Cabling

• SAN implementation use: Imolemantation use
  • short distance copper cable
  • long distance fiber optic cable
• Two Types of Fiber Optic Cables
  • single mode
    • can carry a single beam
    • Distance up to 10 km
  • multimodal
    • Can carry multiple beams at the same time
    • Distance up to 500 meters

Components of SAN: Cabling (Connector

• SC duplex connection duplex GBIC
• LC Dual Regulatory Connection SFP

patch panel connector

• ST simplex connector 单工

Components of SAN: Interconnecting devices

• Hubs
• Switches and
• Director

Components of SAN: Storage array

• Storage consolidation, centralized consolidation, centralization
• Properties of an array
  • availability redundancy
  • performance
  • business continuity
  • multiple host connection

SAN management software

• a suite of tool to manage interface between hosts and storage arrays
• SAN Environment Integrated Management
• Web GUI and CL

SAN interconnectivity Options

p2p

• direct connection between devices
• limited connectivity limited connectivity

FC-AL

Fiber Channel Arbitrated Loop Fiber Channel Arbitrated Loop

• Arbitrate to gain control through arbitration
• hubs connection
• Up to 127 devices

See 17 for details

FC-SW
fabric connect

• dedicated broadband
• 15 million devices
• higher availability

ISL Inter-switch link inter switch link

• ISL uses electronic ports to interconnect two or more FC switches
• Route host-to-storage data and fabric management traffic from one switch to another
• ISL is also the expansion mechanism of SAN

Type port

1. FLOGI fabric login
   1. N F
2. PLOGI port login
   1. between N and N
   2. Nport establishes a session with another Nport
3. PRLI
   1. Between NN
   2. Share information about the type of upper layer protocol being used
   3. The device is identified as a SCSI initiator or target

Lesson Summary

Key topics covered in this lesson:
 FC SAN and its components
 SAN Interconnectivity Options
 Port types and inter switch lin

Lesson: Fibre Channel Architecture

Upon completion of this lesson, you will be able to:
 Describe layers of FC
 Describe FC protocol stack
 Discuss FC addressing
 Define WWN addressing
 Discuss structure and organization of FC Data

FC Architecture Overvie

• channel tech
• Provides high performance with low protocol overhead
• FCP - SCSI-3 over FC network
  • Subtained transmission bandwidth with over long distances
  • 8GB/s
• For details on the fifth floor, see 25
  • FC4 SCSI HIPPI ESCON ATM IP
  • FC2 Farming/Flow Control
  • FC1 Encode/Decode
  • FC0
    • FC-3 is not yet implemented

Fibre Channel Protocol Stack

FC layer	Function	SAN relevant features specified by FC lay
FC-4	Mapping interface	Mapping high-level protocols
FC-3	Common services	not realized
FC-2	Routing, Flow Control	Frame structure, ports, FC address buffer credits
FC-1	Encode/decode	8b/10b encoding, bit and frame synchronization
FC-0	physical layer	media cables connector

Fiber Addressable Channel

• FC address is assigned during fabric (structure) login
  • SAN internal node communication
  • Similar to the IP address of a NIC
• Format:
  • 24 bits
  • dynamic allocation
  • The content of three bytes depends on the N port type
  • For Nport or public Nport
    • The switch maintains the mapping from WWNs to FC addresses through the Name Server

World Wide Names

• unique unique 64-bit identifier
• Static to Port—used to physically identify a port or node in a SAN
  • Similar to the MAC address of a NIC

Structure and organization of FC data

FC data includes:

• Exchange operation
  • Two N_ports can identify and manage a set of information units
  • map to sequence
• sequence (order
  • Contiguous set of frames sent from one port to another
• frame
  • basic unit of data transfer
  • Each frame can contain up to 2112 bytes of payload

Lesson Summary

Key topics covered in this lesson:
 Fibre Channel Protocol Stack
 Fibre Channel Addressing
 Data Organization: Frame, Sequence and Exchang

Lesson: FC Topologies and Management

Define FC fabric topologies
 Describe different types of zoning分区

Core-Edge Fabric

p32

• Can be two or three layers
  • single core layer
  • one or two edge layers
• In a two-tier topology, storage is usually connected to the Core
• Benefits
  availability high availability
  scalability medium scalability
  connectivity medium to maximum connectivity

Mesh

• Global partial or global full mesh
• switch connected to each other
• Hosts, storage can be located anywhere in the structure
• host, storage localized to a single switch

Fabric Management: Zoning

Zoning Components

p 35

Types of Zoni

Key topics covered in this lesson:
 FC SAN Topologies
– Core-Edge
– Mesh
 Fabric management by zoning