ACADEMY

CONFERENCE 2003
EDUCATING TOMORROW’S
NETWORKING PROFESSIONALS.

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 1
 Introduction to
Storage Networking

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 2
 Agenda

• IT Requirements
• Technology Overview
• Storage Applications

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 3
 IT Requirements

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 4
 IT Requirements

• Manageability
• Availability
• Scalability

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 5
 Manageability

• Central point of management for storage

and network
• Easy reconfigurations
• Automated management functions
• Standard-based management tools
• Enhanced security

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 6
 Availability

• Always-on access to data

• Interoperability across heterogeneous equipments
• Data sharing across distributed data centers
• Enhanced security
• Disaster Recovery

Loss of Data is Unacceptable

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 7
 Scalability

• Increased storage capacity

• Increased storage utilization rates
• Optimized network infrastructure
utilization
• Enhanced security

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 8
 Hot Storage Topics

• Server-Free Backup
• Storage virtualization
• IP Storage
• Heterogeneous SAN Management

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 9
 Technology Overview

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 10
 Storage Models
Direct Attach Storage - DAS

• SCSI or FC attached. However SCSI dominates

• Limited scalability & management capabilities
• Block Level I/O
• Distance Limitations
• Lack of device sharing
• Limited ability to scale servers
and storage independently Direct Attach
• Individual points of disk management

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 11
 Network Attached Storage (NAS)
• Servers connected to Ethernet
switch
• Servers can share same filesystem
• Uses TCP/IP
• File Level I/O
• Used in file sharing or low
performance apps
• ‘Unlimited’ scalability
• May use multiple paths

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 12
 Storage Area Network (SAN)
• Servers connected to switch
• Servers can share same subsystem
• Typically uses FC, but can be any
protocol
• Block Level I/O
• Typically deployed in mesh or island,
as a separate network
• Unlimited scalability
• May use multiple paths

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 13
 Storage Architecture Comparison

DAS NAS SAN

Block Oriented File Oriented Block Oriented
I/O I/O I/O
Direct Attached Ethernet Fibre Channel
Parallel SCSI Attached Attached
Supports server Supports client Supports server
applications with applications with applications with
high performing lower performing high performing
parallel SCSI NFS/CIFS Fibre Channel
Install requires Quick and easy Install can be
downing server to install complex
Low scalability Medium High scalability
and scalability and and
consolidation consolidation consolidation

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 14
 SAN Components

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 15
 SAN Components
Host Bus Adapter (HBA)

• Interface between host and storage

• Supports copper or optical
• SC or LC interface, one or two ports
• 1Gb and 2Gb

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 16
 SAN Components
Switch/Director

• 1Gb and 2Gb

• 8-256 Ports
• Low Latency
• Directors use redundant components
• Can be copper or optical

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 17
 SAN Components
Storage

• 1Gb and 2Gb

• 2-32 Ports
• 36GB – 36 TB
• Subsystems may mix interfaces
• ESCON/FICON, SCSI, or FC, NAS
• SCSI or FC disks

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 18
 SAN Components
Tape

• Tape speed vary 5MBs – 30MBs+

• Capacity vary 20GB – 300GB+
• Deployed in servers or external libraries
• SCSI ,FC, Ethernet interface
• DLT most common. LTO gaining traction

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 19
 Fibre Channel
Overview

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 20
 Fibre Channel
Structure & Concepts

• Fibre Channel is a bi-directional, point to point,

serial data channel.
•It provides a general transport mechanism for
Upper Layer Protocols (ULP) e.g. SCSI, HIPPI etc.
•It can be implemented in any of the following
three topologies.
-Point to point link between two N-Ports
-Set of N ports interconnected by a switch
fabric
-A set of L ports interconnected by Arbitrated
loop
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 21
 Fibre Channel – Topologies
Point-to-Point
N_Port 0 N_Port 1

transmitter
transmitter receiver
receiver

receiver
receiver transmitter
transmitter

Simple Node A Node B

Dedicated connection between two N_Ports (initiator and

target)
No ambiguity in addressing and availability
Port characteristics must match (speed, protocol, media)
Rarely implemented

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 22
 Fibre Channel – Topologies
Arbitrated Loop

Devices arbitrate for loop access

NL_Port 0 NL_Port 1
Frames travel in one direction
transmitter
transmitter receiver
receiver
Limited to 127 ports (including 1 fabric
port) receiver
receiver transmitter
transmitter

Loop ID represents an arbitrated loop Node A Node B

physical address (AL-PA)
NL_Port 2 NL_Port 3
Hard AL-PA versus soft AL-PA
transmitter
transmitter receiver
receiver
More economical per connection than
switched fabric ports receiver
receiver transmitter
transmitter

Functional bandwidth determined by Node C Node D

activity & population

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 23
 Fibre Channel – Topologies
Switched Fabric
Provide 100MBps bandwidth
per port
Adding new devices increases N_Port 0 N_Port 1
aggregate bandwidth transmitte transmitter
transmitte transmitter
rr F_Port F_PortX
Cut-through or Store & forward receiver
receiver W receiver
receiver
switching
Node A Node B
Over 16 million possible FABRIC
addresses
N_Port 2 N_Port 3
Loops and fabrics coexist transmitte transmitter
transmitte transmitter
rr F_PortY F_PortZ
Zoning allows isolation of receiver
receiver receiver
receiver
resources & operating
systems Node C Node D

Provides routing based on

destination address
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 24
 Fibre Channel – Topologies
Port Types

Fabric Switch
Node NL_Port FL_Port E_Port E_Port

G_Port F_Port N_Port Node

Node NL_Port
Fabric
Switch
G_Port F_Port N_Port Node
Node NL_Port

G_Port F_Port N_Port Node

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 25
 Storage Features

• Inter-switch Link (ISL) – E Ports

Ability to Connect Multiple
Switches and create larger fabrics FC
FC

Scalability
Bridge Campuses
Extend further over DWDM
Potential Bottleneck
Lack of bandwidth FC FC

When supporting VSANs, called

‘TE’ Ports (trunking E ports)

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 26
 Fibre Channel Scalability Limits (In
Theory)

• 239 Switches per Fabric

256 available Domain IDs minus 17 reserved
• 256 Loops per Switch
• 256 Ports per Switch
• 128 Nodes per Loop
Not all of the AL_PA values can be used on a
loop

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 27
 Fibre Channel
Protocol

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 28
 Flow Control

• Ethernet
Point-to-point Flow Control is optional
ON/OFF protocol (e.g. IEEE 802.3x)
End-to-end flow control is delegated to transport
protocols (e.g. TCP)

• Fibre Channel
Point-to-point Flow Control is mandatory
Implemented by BB_Credit
End-to-end Flow Control is optional
Implemented by EE_Credit

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 29
 Flow Control
Link Level
• Flow control protocols use a Credit count concept. Credit is
the permission granted by the receiving port to the sending
port to send a specified number of frames. Suspend
transmission when credit = # Buffers
• Buffer to Buffer Credit (BB_Credit) is granted during the login
process and depends on interconnection topology.
• When R_RDY is received, BB_Credit is decremented
Transmitting Port Receiving Port
Credit = 1
Credit = 2
Credit = 3
Credit = 4
Credit = 5 R_RDY
Credit = 5 R_RDY
Credit = 4

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 30
 Routing

• Ethernet
Spanning Tree to define an active topology
Local forwarding decisions in each switch
More sophisticated routing delegated to network layer
protocols (e.g. OSPF, BGP)
• Fibre Channel
FSPF to build routing tables into switches
FC_ID Allocation simplifies routing tables
Multiple paths used at the same time
No TTL (Time To Live)
Potential loops may be present during convergence
There is no such a thing as a network layer
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 31
 Fabric Configuration
FSFP – Overview

• FSPF stands for Fabric Shortest Path First

• Based on Link State Protocol
• Begins after Domain ID assignment is completed
• Conceptually based on Open shortest Path First
(OSPF) internet routing protocol
• Currently a standard defined in FC-SW-2

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 32
 Fabric Configuration
FSPF – Components

• FSPF has four major components

Hello Protocol
Replicated Topology Database
A path computation Algorithm
Routing Table Update

• FSPF discovers the paths to switches using

Domain – Ids
• Performs hop-by-hop routing

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 33
 Fibre Channel Session Management

Fabric

FLOGI FLOGI

Accept Accept
Process-A1 Process-B1
PLOGI
PLOGI

Accept
Accept

Process-A2 PRLI
PRLI Process-B2

Accept
Accept

Node-A Switch-A Switch-B Node-B

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 34
 Session Management
Login/Logout – Overview

• Login occurs after the link is Active and IDLEs are flowing in
both direction.
• After the login session a port may originate or respond to
Exchanges.
• Fibre Channel defines three different levels of Login:
- Fabric Login is used to establish a session between the
N_Port and the F_Port
- Port Login is used to establish a session between the two
N_Ports and fabric services.
- Process Login is used to establish a session between the
processes on the two N_Port.
• Login sessions are long-lived and last for multiple exchanges
depending upon application.

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 35
 Session Management
Fabric Login – FLOGI

• FLOGI accomplishes five functions:

- It determines the presence or absence of fabric
- If fabric is present, it provides operating characteristics
associated with the fabric (service parameters like max. frame
size)
- If fabric is present, it optionally assigns or confirms (if trying
to reuse an old ID), the N_Port Identifier of the port initiating the
login
- If fabric is present, it initializes the BB_Credit
- If fabric is not present, it indicates the requesting N_Port of
point to point topology.

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 36
 Session Management
Port Login – PLOGI
• FC standards provide four extended link services to support
N_Port Login:
- N_Port Login (PLOGI) to establish a session between two end
ports.
- N_Port Logout (LOGO) to end a session between two end
ports.
- N_Port Discover (PDISC) to verify existing service parameters
between two end ports.
- Discover Address (ADISC) to discover the mechanism used
to define the other ports address (by switches, jumper or hard
coded)

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 37
 Fibre Channel
Services

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 38
 Standard Fabric Services

Configuration

Name Server
Unzoned
Server

Server
Zone
Domain
Manager
Name
Server Generic
ControllerServices
Alias
Fabric
Server
Management Server
Key
Server
Time
Server

FC-4 ULP Mapping

FC-3 Generic Services Common Transport

FC-2 Framing & flow control Link Services

FC-1 Encoding

FC-0 Physical interface

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 39
 The Domain Manager (cont.)

Management
Management
Services
Services
VSAN
VSANManager
Manager WWN
WWNManager
Manager

Domain Manager

Fabric Principal Switch Domain ID

Configuration Selection Allocation

FC_ID FCID Database

Allocation and Cache

Port
PortManager
Manager Login
LoginServer
Server

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 40
 The Domain Manager (cont.)

Domain ID and FC_ID allocation is on a per-VSAN

basis:
Single FC_ID for F_Port/N_Port
An Area (256 FC_IDs) for FL_Ports

Same FC_ID is allocated for a given WWN on a

best-effort basis.

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 41
 Fabric Configuration
Principal Switch

• A Principal Switch shall be selected whenever at

least one Inter-Switch Link (A link between two
E_Ports) is established.
• The selection process chooses a Principal
Switch, which is then designated to assign
domain identifier to all the switches in the fabric.
FC_ID’s can change!

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 42
 The Name Server

Name Server stores data about nodes, such as:

FC_IDs
WWNs
Fibre Channel operating parameters

Supports soft zoning

Provides information only about nodes in the
requestor’s zone

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 43
 Fibre Channel Names

•The Fibre Channel name is a 64-bit unique identifier to identify

nodes, ports and fabrics used whenever a login session is
established .
•The first four bit of the name identify the Name Assignment Authority
(NAA) and the remaining 60 bits are determined by the format in NAA
field.
• The 48 LSB are based on IEEE 802.1A MAC
address
• For a complete list of NAA identifiers,
refer to pg 113 of FC-PH rev 4.3 NAA Identifiers
63 62 61 60 NAA
0 0 0 0 Ignored
0 0 0 1 IEEE
0 0 1 0 IEEE Extended
0 1 0 0 IP
0 1 0 1 IEEE Registered
0 1 1 0 IEEE Reg Ext.

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 44
 The Alias Server

•Alias Server:
Maps addresses (ALIAS_IDs) to groups of nodes
Aliases are used to support:
Hunt groups
Multicasting
Does not directly support hunting or multicasting—simply
notifies other fabric services when ALIAS_IDs are
assigned

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 45
 The Management Server

•Management Server:
Information is provided without regard to zone—single
access point for information about the fabric topology
Read-only access
Services provided:
Configuration Service
Zone Service
Unzoned Name Service

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 46
 Zoning
• Zones
Why were they invented?
OS’s accessing blocks that do not
belong to them
Security – First Attempt
How are they assigned – WWN, PWWN
Ability to overlap

FC
Zone C
Zone B Overlapping
Zone A
FC
FC

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 47
 Hard Zoning

Defines zones based on physical location

Also known as port zoning

Zone A Zone B

FC FC

Host 1 Host 2

FC FC

Storage 1 Storage 2
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 48
 Soft Zoning

Defines zones based on WWNs, FC_IDs,

aliases, LUN’s
Also known as WWN zoning

FC FC

Host 1 Host 2

FC FC

Zone A Zone B

Storage 1 Storage 2
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 49
 What is a VSAN?
VSAN 3

FC FC FC FC
FC

FC

FC

FC FC
FC FC

VSAN 2
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 50
 Why VSAN’s?
Homogenous “SAN Islands”

FC
Scalability
Share spare ports
FC
FC
FC
FC
FC

ERP SAN across all SAN’s

HR SAN Availability
Separate Servers per
VSAN
Security
FC
No access across
FC
FC
VSAN boundaries
Engineering SAN (NT separate from
UNIX, etc)

Midrange DAS

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 51
 Comparing VSANs and Zones

VSANs Zones
Functionality Separate routing, naming, Routing and naming are fabric-
and zoning for each VSAN wide
Isolate all traffic Isolate unicast traffic only
Membership Fx_Ports F_Ports or WWPNs

Each port can belong to Each port can belong to

one VSAN multiple zones

Security Enforced at TE_Ports, source Enforced at source and

port, and destination port destination ports only

Use Redundant fabrics, high- Separate Windows and UNIX

security configurations, test devices, fabric traffic reduction,
environments, etc. additional security

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 52
 SAN Architecture & Topology

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 53
 SAN
Dual Star Topology

Application

‘A’

Application

‘B’
Shared Storage
Resources SAN Fabric

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 54
 SAN
N-Wide Star Topology

Application

‘A’

Application

‘B’
Shared Storage
Resources

Application

‘C’
SAN Fabric

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 55
 SAN
Mesh Topology

Application

‘A’

Application

‘B’
Shared Storage
Resources SAN Fabric

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 56
 SAN
Ring Topology

Application

‘A’

Application

‘B’
Shared Storage
SAN Fabric
Resources

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 57
 SAN
Ring+Star Topology

Application

‘A’

Application

‘B’
Shared Storage
Resources

SAN Fabric

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 58
 SAN
Core-Edge Topology

Application

‘A’

Application

‘B’

Shared Storage SAN Fabric

Resources

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 59
 Business Requirements

RAID, Multipathing, Clustering, Replication

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 60
 Methods of Disaster Recovery

• Three data protection methods:

1. Backup and Restore
2. Replication and Failover
3. Geographically Dispersed Clustering
Data is usually stored and recovered from
an offsite disaster recovery center

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 61
 RAID levels

RAID Level Description Min Disks

0 Striping/Concatenation 2/1

1 Mirror 2

0+1 Striping/Concatenation then Mirror 4

1+0 Mirror then Striping/Concatenation 4

2 Hamming Code N/A

3 Fix parity with concert I/O N/A

4 Fix parity with Random I/O 3

5 Stripe with distributed parity with 3 without log

Random I/O 4 with log

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 62
 Multipath I/O Design

• A redundant I/O design

• Dynamic failover and recovery
Host with dual
FC HBAs
and Multipathing
Software Installed
Storage Array with
Redundant Controller
Ports
Application FC Switches
Multipathing
HBA Driver

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 63
 Multi-Pathing Solution
Manages multiple paths to a storage system
• Intelligent path selection - Load Balancing
Increased Performance and Throughput

• Automatic Error Detection and Path Failover

Application and Business Continuance
Dynamic Recovery

• Minimizes System Administrative Planning

i.e.: Volume and/or Striping Decisions related to paths and
width
Dynamic Configuration
Application, Database, File System, Management
Utilities and Volume Manager Independent
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 64
 Data Replication

Any technique used to copy data

Can be used for disaster recovery, data
publication, data consolidation, and data
movement
Industry terminology is not consistent
Often called mirroring or remote mirroring
Mirroring is a type of replication

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 65
 Replicating Data Locally (Mirroring)
Host Based Subsystem Based
Software on
server creates Server
duplicate copies Server
of data on disk
subsystem Subsystem
Second Write Server manages
Write copying data
internally or
SAN between
SAN
subsystems

FC
FC FC
Primary Copy FC
Mirrored
of Data Mirrored Primary
Copy of Data Copy Copy of
of Data Data

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 66
 Mirror Member Assignment in an Array

Card CPU [LUNs]

2 a [020 021 022 023 ] [026 027 028 029 02a] ………
b [030 031 032 ] [050 051 052 053 ] ………

3 a
b
.
.
.
14 a
b

15 a ………. [030 031 032 ] [050 051 052 053 ]

b ………. [020 021 022 023 ] [026 027 028 029 02a]

By following this layout type, maximum diversity is achieved –

Mirror members are on different fc ports, cpu’s, busses, etc.
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 67
 Replication over Distance
Data Center 1 Data Center 2

Distance extended
To 10 KM

FC

SAN SAN
FC

FC FC
FC FC

Directly impacts the Business

Covering the Distance with SAN
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 68
 Replication: Synchronous
Site 1 Site 2
Transport Method
Server Native Fibre Channel
(up to 10km)

MAN/WAN
SAN SAN

FC
FC
Synchronous

•Acknowledged copy
•Delay sensitive
•High bandwidth
required 69
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved.
 Replication: Asynchronous
Site 1 Site 2
Transport Method
Server Fibre Channel over IP
(FCIP/DWDM/SONET)

MAN/WAN
SAN SAN

FC
FC
Asynchronous

•No confirmed copy

•More delay tolerant
•Less bandwidth
required 70
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved.
 Backup Methods

Off-Line (cold) backup

Must be done within the backup window
On-Line (hot) backup
Ignores the backup window, but creates heavy system
resource conflicts
Difficult to maintain data integrity
Raw device (image) backup
As cold as it gets
Difficult to restore individual files

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 71
 Backup Levels

•Full:
Backup whole volume or file system
Requires the most backup time
Requires the fewest amount of tapes for restoration
Limited to weekends
•Incremental:
Backup only the changes since the last backup
•Differential:
Backup only the changes since the last full backup

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 72
 Snapshots

•Also called:
Point in Time Copies
Frozen Images
Checkpoints
•Common implementations use:
Split Mirrors
Copy on Write

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 73
 Split Mirror Snapshot

Two Stage Mirrors

•M1, M2, and M3 are all
members of a single RAID copy
FC •M3 is split from the group to
provide a backup or
development image
•No impact to availability

M1 M2 M3
FC

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 74
 Clustering
•Scalability
Ability to support increasing numbers of
users
Ability to provide extra capacity by FC
FC

adding extra servers

•High availability
Redundancy: many machines to service
requests
One machine fails, another transparently
takes over
FC
Rolling Upgrades FC

•Performance
More processors divide the workload
where applications can be done as
parallel processes
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 75
 IP Services

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 76
 What is iSCSI?

iSCSI

iSCSI
FC

Servers with Ethernet FC

iSCSI drivers
iSCSI
Fibre Channel
or FC storage
iSCSI NICs
with TOE
iSCSI
Ethernet iSCSI to FC
Switch Gateway

iSCSI

Initiators—iSCSI HBAs (or NICs) function as

iSCSI
SCSI ‘masters’

Targets and LUNs—iSCSI devices and

subsystems take the role of SCSI ‘slaves’
Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 77
 The FCIP Protocol

•FCIP—Fibre Channel over Internet Protocol

The Encapsulation of Fibre Channel frames into IP packets and tunneled through
an existing IP network infrastructure
FC
FC Tape Server
FC Server
Library
FC Tape
Library

FC Switch FC Switch
FC Switch FC Switch
Fibre IP Network Fibre
Channel Tunnel Session Channel
SAN SAN
FC Switch
FC Switch
FC Switch FC Switch

FC FC
Server FC FC disk subsystem
disk subsystem Server

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 78
 Potential FCIP Environments
Local Remote
Datacenter Datacenter
• 1Gb->OC48 or Higher
Gateway Gateway
• Relatively low latency Metro
FCIP Ethernet FCIP
• Synch/Asynch SAN SAN
Applications

Short distance ~ <= 60km

Local Remote
• Typical OC3 / OC12 Datacenter Datacenter
• Relatively low latency Gateway Gateway
• Mainly asynchronous FCIP SONET FCIP
SAN SAN
• Suitable for some
synchronous apps
Medium distance ~ <= 160km

Local Remote
• Low speed (T1–DS3) Datacenter Datacenter
• Higher latency
Gateway Gateway
• Longer distance IP Routed
FCIP WAN FCIP
• Mainly asynchronous SAN SAN

Long distance > 160km

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 79
 FCP, FCIP and iSCSI
•FCP: Local SANs
•FCIP: SAN-to-SAN over IP
•iSCSI: Host to FC-SAN over IP

SI

iS
C

C
iS

iSCSI gateway
IP Network

SI
iSCSI gateway

FCP FCP
FCIP

FCIP gateway FCIP gateway

Cisco Storage Networking - Dan Hersey © 2002, Cisco Systems, Inc. All rights reserved. 80
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