2014 LENOVO. ALL RIGHTS RESERVED. SAN Fundamentals.

2014 LENOVO . ALL RIGHTS RESERVED.

SAN Fundamentals

2 2014 LENOVO. ALL RIGHTS RESERVED.

Distributed Model of data flow Direct Attach Storage SCSI Protocol SCSI addressing / subaddressing Fiber Channel Centralizad Model of data flow Storage Area Networks Topologies Management of SAN Zoning ISL Architecture

Agenda


Data is written to, and retrieved from, a disk drive Typically via local application

or server application

Applications / file systems utilize block-level I/O Send/retrieve data via I/O blocks

Users utilize file-level I/O Send / retrieve data files

0 1 1 0 1 0 0 1 0 1 0 1 1 1 0 1 0 1 0 0 0 1

Data And Disks


Yesterday’s View of Information


DAS Device DAS Device

Direct Attached Storage


Storage is directly connected to a single server SCSI, SAS, iSCSI, Fibre Channel Block-level I/O

Internal drives With or without RAID protection

External drives Storage system

Controller-based RAID engine



Motherboard

HA

External storage system connected via host adapter

• Controller-based RAID

Controllers

ApplicationServer

External DAS


Connects to Server using SAS or SCSI Maybe JBOD or RAID

DAS Device

Server

SCSI or S

AS



Issues Limited distance

Server

SCSI or S

AS



Issues Limited distance Limited number of devices (SCSI) Limited redundancy

Server

SCSI or S

AS



The point−to−point topology in DAS



External DAS Advantages

Low-cost Drives are typically included with the server

Immediate utilization Some data protections

Internal DAS Advantages

Better than data stored on clients Increased availability and performance

RAID protections Increased features and functionality Scalability



DAS Disadvantages

Each server has its own storage device ($$) Management is difficult

Reduced Productivity Expensive to backup Wasted storage space Difficult to share data



Shared DAS

Storage is directly connected to a single server SAS, iSCSI, Fibre Channel

Storage system consist of RAID controllers and drive enclosures RAID engine is controller-based



Host Bus Adapter


The initiating device is a device that looks for and communicates with target devices.

It is commonly referred to as the host bus adapter (HBA), and it resides in the server or client workstation.

The significance of the HBA is that it actually is an active device that seeks out its targeted pair to communicate with so as to achieve a file transfer.

The HBA has the ability to monitor its path to its targeted pair. If, for some reason, it loses contact with the target, the initiator will

switch to an alternate target.

In order for this event to occur, one level of redundancy is put in place

whereby there are dual initiators, dual switches, and mirrored disks.

Host Bus Adapter


Small Computer System Interface (SCSI)SCSI is a protocol for connecting computers with external

devices for data management or data protectionIt defines: Commands: These are standards that define specific

command sets for either all SCSI devices, or for particular types of SCSI devices.

Protocols: These standards formalize the rules by which various devices communicate and share information, allowing different devices to work together. These standards are sometimes said to describe the transport layer of the interface.

Interconnects: These are standards that define specific interface details, such as electrical signaling methods and transfer modes. They are sometimes called physical layer standards as well.

What Does SCSI Stand For?


An industry standard I/O Bus Standard connectors are the same on each device

All devices share a common bus

8-bit data bus 16-bit data bus

The SCSI interface….started it all!


Disk Drives Tape Drives Removable Media Drives (Zip) CD-ROM Drives CD-R/CD-RW Drives Optical Memory Drives Media Changers

What Types of Devices Use SCSI?


Server SAS HBA or SCSI adapter RAID sub-system

SCSI or SAS

Ethernet to Clientworkstations

Dual Controller RAID with only one controllerin use (B not used in this example). This RAID system has four SCSI buses with five drives on each bus.

Controller

SCSI/SAS

Chip

Controller

SCSI/ SAS

Chip

initiator

target

Where do SCSI and SAS fit in?


LUNs are a type of sub-addressing supported by SAS and SCSI

LUNs are selected through the Identify message

Host Adapter

ID 7

Controller

ID 1

Disk Drive

LUN 0

Disk Drive

LUN 1

Controller

ID 2

Disk Drive

LUN 0

Disk Drive

LUN 1

Logical Unit Number (LUN)


RAID 0: Striped set without parity (Non-Redundant Array). Fastest and most efficient level but offers no fault tolerance

RAID 1: Mirrored set without parity neither striping. Provides fault tolerance from disk errors and failure of all but one of the drives. Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing

RAID 3:Striped set with dedicated parity/Bit interleaved parity. This mechanism provides an improved performance and fault tolerance similar to RAID 5, but with a dedicated parity disk rather than rotated parity stripes .

RAID 5:Striped set with distributed parity. Distributed parity requires all drives but one to be present to operate; drive failure requires replacement, but the array is not destroyed by a single drive failure. Upon drive failure, any subsequent reads can be calculated from the distributed parity such that the drive failure is masked from the end user

RAID 1+0: High performance but requires double the number of drives for mirroring of data.It allocate blocks in stripes along the disks.

Redundant Array of Independent Disks


SCSI SAS Fibre Channel

Cable Distances

3 meters 8 meters Up to 10Km

Duplex Half Full Full

Devices 12 ~ 16k with expanders

224 -confirm

Throughput 320 MB/s 3Gb/s* 4Gb/s* Up to total 12Gb/s throughput with wide ports

SCSI and SAS vs. Fibre Channel


A transport mechanism for multiple protocols SCSI-3 and SAS Internet Protocol (IP) others

What is Fibre Channel?


Serial Transmission Smaller Connectors Eliminate Skew problems of parallel transmission

High bandwidth 1, 2 , 4, 8 and 16 gigabits per second (Gb/s)

Big "B" versus little "b" Megabit is abbreviated with a lower case b (Mb) Megabyte is abbreviated with a capital B (MB)

Why Fibre Channel?


Scalable Large number of devices Greater distance Transport mechanism for multiple protocols

Why Fibre Channel?


Permits Switching Avoids problems of shared media and shared

bandwidth Allows mixed speeds

Auto-negotiating , can adjust throughput to lower speeds

Transport mechanism for multiple protocols

Why Fibre Channel?


Topology Number of Devices

Point to Point 2

Arbitrated Loop Up to 127

Switched Fabric Up to 16 million

Connectivity


Processor

Memory

I/O Bus

Computer

N_Port0Bridge

TX

RX

RX

TX

Storage subsystem

100 MB/s

100 MB/s

Full Duplex (Fibre Channel example): 4Gbps + 4Gbps = 8Gbps (theoretical)

N_Port1

Point to Point


Input to fiber Output from fiber

Multiple path-lengths, or modes, permitted by the fiber smear the shape of the pulse

150 meters

Multimode Fibre


Single path-length, or mode, imposed by the fiber preserves the shape of the pulse

Input to fiber Output from fiber

Single Mode Fibre


Server

HBA

RAID sub-systemFibre Channel


Dual Controller RAID with only one controllerin use (B not used in this example). This RAID system has four SCSI buses with five drives on each bus.

Controller

SCSIChip

Controller

SCSIChip

Basic Configuration


ServerRAID sub-system

HBA Fibre Channel


Dual independent controllers with automatic fail-over for continuous availability in case one controller or one fiber link fails.

HBA Fibre ChannelController

SCSIChip

Controller

SCSIChip

Sample SCSI/SAS subsystem

Dual Controller Configuration


Server

HBA FC/SAS



HBA

Controller

Controller

FC/SAS

FC/SAS

Fibre and Storage subsystem

RAID

FC/SAS

Dual Controller Configuration


Server

HBA Fibre Channel



HBA Fibre Channel

Controller

Controller

Fibre Channel

Fibre Channel

Storage Device

RAID

Connectivity at SAN


Switch

Switch

Switch

Switch

NAS

NAS

NAS

RAID

A B

A B

A B

A B

A B

A B

Storage Area Network

(SAN)

A B

Storage subsystem

Servers

ServersNetwork Attached Storage

(NAS)

Connectivity at SAN


Mainframe

Information

Finance

SupportOperations

Purchasing

NT

UNIX

NAS

Centralizing Information


Unused storage capacity may be easily allocated to servers as need.

Distributed Storage Centralized Storage

Centralizing Information = Value


What is a Storage Area Network (SAN)?


A SAN is a specialized, high−speed network attaching servers and storage devices. It is sometimes called "the network behind the servers.“

A SAN allows "any−to−any" connection across the network, using interconnect elements such as routers, gateways, hubs, switches, and directors.

It eliminates the traditional dedicated connection between a server and storage, and the concept that the server effectively "owns and manages" the storage devices.

It also eliminates any restriction to the amount of data that a server can access, currently limited by the number of storage devices, which can be attached to the individual server.

Instead, a SAN introduces the flexibility of networking to enable one server or many heterogeneous servers to share a common storage utility, which may comprise many storage devices, including disk, tape, and optical storage.

The storage utility may be located far from the servers that use it.

SAN: Storage Area Network


When an application on the network requests information, the request is handled by a server and the correct blocks of data are returned to the client.

Databases are probably the largest example of block level data access in the data center today.

0 1 1 0 1 0 0 1 0 1 0 1 1 1 0 1 0 1 0 0 0 1

Block Level Access – SAN and DAS


Users work at the file level (ie. Word files, excel spreadsheets. etc) and then the applications we use change these to block level data

Block level must go through the server first

Block Data to File


• External storage system connected to SAN

• Controller-based RAID

Controllers

Block-level access

Application Server

Application Server

Application Server

Switch

0 1 1 0 1 0 0 1 0 1 0 1 1 1 0 1 0 1 0 0 0 1

Storage Model for SAN


High-bandwidth capable of growing incrementally Transfers very large blocks of data Offers storage applications such as backup and

remote mirroring without bogging down LAN Superior performance, reliability and flexible

connectivity

Advantages of SAN


SAN benefits


The major features that a well−designed SAN offers include:

High bandwidth—1Gbps to 10Gbps Disaster recovery plans Business continuity plan Manageability Easy integration Lower total cost of ownership

Well-designed SAN


Infrastructure for easy storage connectivity and growth Easy management Performance “Freedom”

-Connecting everywhere every device into the same storage network (SAN)

-On Line adding devices

Key benefits of a Centralized SAN


Fibre Channel Connectivity


Logical Topologies


Topology 1: Point – to - Point


Computer

Processor

Memory

I/O Bus

N_Port0

BridgeTX

RX

RX

TX

DriveEnclosure

N_Port1

Controller

Point to Point

Transmit (TX)Receive (RX)


Topology 2 : Arbitrated LOOP


TX

RX

NL_port 0

TX

RX

NL_port 3

RX

TX

NL_port 1

RX

TX

NL_port 2

127 Nodes Maximum, Typical 5-30

Fibre Channel-AL

Fibre Channel Arbitrated Loop


TX

RX

NL_port 0

TX

RX

NL_port 3

RX

TX

NL_port 1

RX

TX

NL_port 2

127 Nodes Maximum

HUB



HUB

TX

RX

NL_port 0

TX

RX

NL_port 3

RX

TX

NL_port 1

RX

TX

NL_port 2

127 Nodes Maximum

By pass defective or unused ports



Topology 3: Switched Fabric


Fabric

TX

RX

N_port 0

TX

RX

N_port 1

TX

RX

N_port 2

TX

RX

N_port 3

TX

RX

N_port 4

224 = 16 million nodes possible

F_port AF_port E

F_port D

F_port C

F_port B

Switched Fabric


Ethe

rnet

hub

or s

witc

h A

B

subsystem

Server 1

HBA

HBA

HBA

Server 2

HBA

Fibre Channel switch

Ethernet to client workstations

Fully Redundant SAN


A

B

subsystem AServer 1HBA

HBA

HBA

Server 2

HBA

Fibre Channel switch

A

B

subsystem B

Adding Capacity


A switched SAN


SAN Model


SAN Infrastructure


SAN Components

SAN Network


SAN ComponentsSAN Servers

The server infrastructure is the reason for all SAN solutions. This infrastructure includes a mix of server platforms such as Windows, UNIX (and its various flavors), and z/OS. With initiatives such as server consolidation and e−business, the need for SANs will increase, making

the importance of storage in the network greater.

SAN Storage

The storage infrastructure is the foundation on which information relies, and therefore must support a company's business objectives and business model. In this environment simply deploying more and faster storage devices is not enough.

A SAN infrastructure provides enhanced network availability, data accessibility, and system manageability.

It is important to remember that a good SAN begins with a good design.

SAN Interconnects

The first element that must be considered in any SAN implementation is the connectivity of storage and server components typically using Fibre Channel.

It uses special connectivity devices


SAN operability


Fibre Channel layers


SAN Architecture


Fabric Channel layers

Lower Layers

FC−1 defines encoding schemes. These are used to synchronize data for transmission.

FC−2 defines the framing protocol and flow control. This protocol is self−configuring and

supports point−to−point, arbitrated loop, and switched topologies.

Upper Layers Fibre Channel is a transport service that moves data quickly and reliably between

nodes. The two upper layers enhance the functionality of Fibre Channel and provide common

implementations for interoperability.

FC−3 defines common services for nodes. One defined service is multicast, to deliver one transmission to multiple destinations.

FC−4 defines upper layer protocol mapping. Protocols such as FCP (SCSI), FICON, and IP can be mapped to the Fibre Channel transport service.


SAN High Level


This is the storage area network:


Zoning

It could be considered as a security feature and not just for separating environments.

Zoning could also be used for test and maintenance purposes.

Zoning also introduces the flexibility to manage a switched fabric to meet different user group objectives.

Zoning can be implemented in two ways:

-Hardware zoning

-Software zoning


Zoning

Hardware zoning is based on the physical fabric port number


Zoning Software zoning is implemented by the fabric operating systems within

the fabric switches. When using software zoning, the members of the zone can be defined using their WWN and WWPN.


ISL Trunking Trunking is a feature of switches that enables traffic to be distributed across available inter−switch links (ISLs) while still preserving in−order delivery.


Fiber Channel types of ports

E_Port: This is an expansion port. A port is designated an E_Port when it is used as an inter−switch expansion port (ISL) to connect to the E_Port of another switch, to enlarge the switch fabric.

F_Port: This is a fabric port that is not loop capable. It is used to connect an N_Port point−point to a switch.

FL_Port: This is a fabric port that is loop capable. It is used to connect an NL_Port to the switch in a public loop configuration.

G_Port: This is a generic port that can operate as either an E_Port or an F_Port. A port is defined as a G_Port after it is connected but has not received a response to loop initialization or has not yet completed the link initialization procedure with the adjacent Fibre Channel device.


L_Port: This is a loop−capable node or switch port. U_Port: This is a universal port—a more generic switch port than a G_Port.

It can operate as either an E_Port, F_Port, or FL_Port. A port is defined as a U_Port when it is not connectedor has not yet assumed a specific function in the fabric.

N_Port: This is a node port that is not loop capable. It is used to connect an equipment port to the fabric.

NL_Port: This is a node port that is loop capable. It is used to connect an equipment port to the fabric in a loop configuration through an L_Port or FL_Port.

Fiber Channel types of ports


Types or ports

2014 LENOVO. ALL RIGHTS RESERVED. SAN Fundamentals.

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Transcript of 2014 LENOVO. ALL RIGHTS RESERVED. SAN Fundamentals.