AIX Ver. 4 SysAdmin IV:Storage Management (Unit 9) – Storage Area Network (SAN) Concepts

Unit Objectives
Explain what a Storage Area Network is
Detail the benefits of SAN technology
Understand the fabric concept
Describe the benefits of Fibre Channel technology

What Is SAN?
Managed, high-speed network that enables the any-to-any interconnection of multi-vendor servers and storage systems and allows companies to exploit the value of their business information via universal access and sharing of resources.

SAN Promises
– Consolidation of storage
– Data sharing
– Improved backup/recovery
– Disaster tolerance
– Higher availability
– Improved performance
– Selection of “best in class” products
– Easier migration to new technologies
– Centralized, policy-based management

SAN Infrastructure
Storage – Disk Storage, FC RAID controller, Intelligent Storage Server, Tape drive/library
SAN Fabric – Switch, Hub, Router, Gateway, Bridge
Software – Applications, Services

Data Sharing Concepts and Types
Storage Subsystem-Based Sharing
– Shorage Sharing
– Data-Copy Sharing
– “True” Data Sharing

SAN Concept
Network & LANS
Storage Area Network
Note: Any Client can access and data on the SAN.

Disk and Tape Storage Consolidation
Islands of information
– Distributed servers and storage
– Separate storage management
– Separate islands of information
Consolidated storage
– Consolidated storage systems
– Consolidated storage management
– Consolidated enterprise data

Storage Area Networks can provide consolidation benefits without physical consolidation.

Outboard Copy
SCSI-3 Command
Server Initiated
Performed by subsystem or device
Block Level – Most file systems have no knowledge of physical blocks used

Remote Copy
Data consistency across subsystems is key
Requires automation – Geographically Dispersed Parallel Sysplex (GDPS)

SAN Applications
Shared Repository, Data Sharing, Network Architecture, Data Vaulting & Backups, Data Protection, Data Interchange, Clustering, Disaster Recovery

What Is Fibre Channel?
A Serial interface technology
Set of open standards for:
– Media and physical interfaces, copper and optical
– Data transmission, link services and signalling protocol
– Mapping of upper level protocols (different command sets: SCSI, HIPPI, IP, IPI-3, ATM, FICON)
Has three topologies:
– Point-to-point
– Arbitrated Loop
– Switched
Enabling Technology for Storage Area Networks
– High Bandwidth – today 100 MB/s per link
– Up to 10 Km LINK distance supported, more with repeaters (up to 100 Km)
– Supports large, scalable configurations
– Hot plugging, reconfigurations

Benefits of Fibre Channel
– Up to 16 million addresses
Storage at a distance
– Up to 100 KM
Performance and throughput
– Up to 100 MB/s per link today
– Up to 800 MB/s between a server and a storage subsystem
Multiple protocols
– FCP(SCSI), FICON, HIPPI, and also IP, IP1-3 ATM

What is a Node? Port? Link? Fabric?
A Node is the source or destination for information being transported.
A Port is the hardware entity within a Node that performs data communications over the Fibre Channel
A Link is a connection between Two Fibre Channel prots consisting of a transmit and receive fibre.
The Fabric is the means by which the Fibre Channel connects devices.

World Wide Name (WWN)
The IEEE company_id is a registered and guaranteed unique 24-bit number
– Proveded for a reasonable fee to all companies that require a value to distiguish their components from all other components in the world.
– One company can have many id:s
– For example 000000-000009 = Xerox
– The assignments of these values are public, so that a user of an identifier defined by ANSI X3.230 can identify the manufacturer that provided the value.
The 24-bit (3 byte) unique number can be found at:

10:00 : 00:47:11 : 00:47:11
Format, Company_id Component number
1000 – Standard
2000 – Extended

Fibre Channel Topology
There are three topologies in the Fibre Channel environment:
Arbitrated Loop

Control the electrical protocol for communications
– Netfinity FC PCI Adapter
– Network Interface Cards (NIC)
– Enterprise System Connection (ESCON)
– Fibre Channel Connection (FICON)
– Host Bus Adapters (HBA)
– SCSI host bus adapters

Cables and Connectors
Copper (30m distances, DB9 (9-pin connector)
Optical fiber
– 9 micron single-mode longwave up to 10 km
– 50 micron multi-mode shortware up to 500 m
– 62.5 micron multi-mode shortware up to 175 m
Gigabit link Model (GLM)
– Fibre Channel transceiver
Gigabit Interface Converter (GBIC)
– Signal translation copper/fiber optic
– Media Interface Adapters (MIA)
– Optical interface connection (typically used by host bus adapter)

IBM SAN Data Gateway Router
– Contains a single Fibre Channel port
– Provides two Ultra SCSI ports, either single-ended or differential
– Attaches new or existing SCSI-based tape libraries to:
-Fibre Channel host systems
– IBM Fibre Channel Switch
– IBM Fibre Channel Storage Hub
– IBM Netfinity Fibre Channel Hub
A Router is basically a protocol converter

IBM SAN Data Gateway
– One to three Fibre Channel Arbitrated Loop ports
– Each loop capable of up to 100 MB/s bandwidth
– Four Ultra SCSI Differential ports standard
– All FC-ports “see” all SCSI ports
– SCSI prots can be assigned to a FC port
– StorWatch SAN Data Gateway Specialist included
– Separte Gateways for ESS and Tape
– No LUN-masking today

Generally a Gateway interconnects dissimilar networks or devices
In traditional networks they are, for example, used for LAN over WAN
One use of a Gateway could be to extend a SAN across a WAN
A Gateway may emulate, for example, a switch

A Hub
– Internally one loop at 100 MB/sec
– Each attachment extends internal loop
– Bandwidth shared between all connected loops

Benefits of a Hub
– Ease configuration of FC-ALs
– Add distance
– Isolate failures

Bypass if connected loop breaks

Any-to-any connection
– Servers, Storage Systems, Other switches (cascading), FC-ALs
Zoning (Restrict any-to-any)
– Hardware (Port based), Software (World Wide Name WWN based)
Device or LUN-masking
– Potential future option

Fibre Channel Repeaters are required to provide extend distance over 10 km
Wave Division Multiplexors provide multiple Fibre Channel paths over a single fibre

SAN Implementation Challenges
How can you implement the following configuration?
– Each server should see only designated disk subsystems, and both should see the tape? You need ZONING

What is ZONING?
Allows a finer segmentation of SANs
Used to set up barriers between different environments:
– Deploy logical Fabric subsets by creating defined user groups
– Create, test and/or maintenance areas that are separate within the Fabric
Allows the flexibility to mange a SAN to meet different closed user groups objectives

Management Considerations
Capcity planning
– Capacity changes
Performance monitoring
– Discover bottlenecks
– Discover overload source
– Divide performance for different needs
– Divide cache-use for different needs
– Load balancing

Disk Pooling
Within a subsystem
Cross subsystems
Single vendor, Multi vendor
Automatic Space Allocation

File Pooling

Tape Pooling
Drive management
Media management
Within application (TSM)
Amoung application (In multiple servers)

SAN Component Management (StorWatch)
Remote switch fabric management
– Netscape or IE browser interface
– Windows NT or UNIX host

Mangement tools
– General switch view
– Performance view
– Port detail view

Administrative tools
– Administrative interface
– Telnet interface
– Pop-up help for error conditions

Do You Need a SAN?
Increase data centralization
Centralized management of centralized data storage system
I/O Operations include very large files
Comprehensive disaster prevention and recovery
High I/O demand (like OLTP – On-line Transaction Processing)
50+ users on the network

Unit Summary
Storage Area Network is a high-speed network of interconnected servers and storage devices.
Fabric is the means by which Fibre Channel connects devices
The benefits of SAN technology include improved performance, greater connectivity and the elimination of redudant data.

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