Basic Training on Storage Technologies

8/8/2019 Basic Training on Storage Technologies

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Basic Training on StorageTechnologies

Introduction& Concepts

June 08 -09, 2009


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The storage upgradationprocess

End user demands more disk/storagespace


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The storage upgradationprocess -2

SCSI / Fibre channel /SATA

Host Bus

Adapter(HBA)Diskdrive

OPTION 1: Additional disk(s) may be added


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The storage upgradationprocess -3

System providing disks ace

Networklink

OPTION 2: Disk space may be shared from anothersystem on the network

System requiring disks ace


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Creating a file systemTo make the new disk usable a filesystem has tobe created on the whole or part of the disk

Partition 1

Partition 2

Partition 3

Partition 4

DiskDisk

DiskDisk

One File-system

One File-systemOne File-systemOne File-systemOne File-

system


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Redundant Array ofIndependent Disks(RAID-0)

RAID-0: Data is stripedacross all the disks in thearray

Block 1 Block 3Block 2

Block 5

Block 4

Block 7Block 6

Block 9

Block 8

Block 11Block 10 Block 12

Block 14Block 13 Block 16Block 15

1 2 3 4 7 85 6

9 10 11 12 1513 14 16

DataBlocks

Layout of the data blocks onthe disks

Disk 1Disk 1 Disk 2Disk 2 Disk 3Disk 3 Disk 4Disk 4


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RAID-1: Data is mirroredfor all the disks in thearray

Block 1

..

Block1Block 2 Block 2

Block 3 Block 3

Block 4Block 4

1 2 3 4 ..DataBlocks

Layout of the data blocks onthe disksDisk 1Disk 1 Disk 2Disk 2

..


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RAID-3: Data is stripedwith a single parity diskfor redundancy


Block 5

Block 4

Block 7Block 6

Block 9

Block 8

Block 11Block 10 Block 12

Block 14Block 13 Block 16Block 15

1 2 3 4 7 85 6

9 10 11 12 1513 14 16

Data

Blocks

Layout of the data blocks onthe disksDisk 1Disk 1 Disk 2Disk 2 Disk 3Disk 3 Disk 4Disk 4

Parity

Parity

ParityParity

DiskDisk

Parity

Parity


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Parity

Block 16

Block 12Parity

Parity


RAID-5: Data is stripedwith distributedparityblocks


Block 5

Block 4

Block 7Block 6

Block 9

Block 8

Block 10 Block 11


1 2 3 4 7 85 6

9 10 11 12 1513 14 16

Data

Blocks

Layout of the data blocks onthe disksDisk 1Disk 1 Disk 2Disk 2 Disk 3Disk 3 Disk 4Disk 4

Parity

ParityParity

DiskDisk


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Parity

Block 15

Block 11Parity

Parity


RAID-6: Data is stripedwith two distributedparity blocks


Block 5

Block 4

Block 7Block 6

Block 9

Parity

Block 10 Parity

Block 13 Block 14

Parity

1 2 3 4 7 85 6

9 10 11 12 1513 14 16

Data

Blocks

Layout of the data blocks onthe disks


Parity

Disk5Disk5

Block 16

Block 12

Block 8

Parity

Disk6Disk6


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Block 7

Block 6

Block 4

Independent Disks(RAID-10)

RAID-10: Data blocks are mirroredand thenstripedacross disks


Block 3

Block 2

Block 4Block 3

Block 5 Block 5 Block 6


1 2 3 4 7 85 6Data

BlocksLayout of the data blocks on

the disks


Mirrored Mirrored

Striped


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Block 8

Block 5

Block 4

Independent Disks(RAID-01)

RAID-01: Data blocks are stripedand thenmirroredacross disks


Block 3

Block 2

Block 3Block 4

Block 5 Block 6 Block 6


1 2 3 4 7 85 6Data

Blocks Layout of the data blocks onthe disks

Disk 1Disk 1 Disk 2Disk 2 Disk 3Disk 3Disk 4Disk 4

Striped Striped

Mirrored


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Host-based RAID

Implementation of RAID configurations usingprograms on the host system.

Independent of hardware configuration

Tightly integrated with host OperatingSystem Each operating system has its ownsoftware RAID implementation:

Solaris Disk Suite, Volume manager

Linux,IBM LVM

SGI XVM

Third party RAID software also exist e.gVeritas Volume Manager


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Limitations of host-basedRAID

1. Limited Filesystem size

The solution:

Use an EXTERNAL RAID-based StorageArray

2. All RAID operations are additional

overhead on the CPU

3. Storage space cannot be shared bymultiple systems


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Advantages of StorageArrays

1. Huge storage capacities upto PetaByte(1015 ) levels

2. Totally self contained -independent of the

host s processing power3. No wastage of storage space available

capacity can be distributed amongmultiple hosts

4. More reliable can be configured with no

Single Point of Failure (SPOF)

5. Negligible backup window

6. Remote replication possible forovercoming disaster situations.


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Hardware RAID StorageArrays

Implementation of RAID using hardwarecontrollers

BE-0

BE-1

DISK

DISK

DISK

DISK

FE-1

FE-0

LOOP

-1

LOOP

-0

Cache

RAIDController

Storage Array

Fiber Channel/

iSCSI

Links

RAID Controller


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Components of a ModularStorage Array

1. Hard disk drives

2. RAID controller(s) having front-end(FE) &

back-end(BE) ports. FE ports are attachedto the hosts while BE ports are connectedto the Disks

3. Battery-backed Cache


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The Hard Disk Drive :Internals


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The Hard Disk Drive :The Actuator


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The Hard Disk Drive :Platters


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The Hard Disk Drive :Spindle speeds

Spindle Speed(RPM)

Average Latency (HalfRotation) (ms)

Typical CurrentApplications

3,600 8.3 Former standard, nowobsolete

4,200 7.1 Laptops

4,500 6.7 IBM Microdrive, laptops

4,900 6.1 Laptops

5,200 5.8 Obsolete

5,400 5.6 Low-end IDE/ATA,

laptops

7,200 4.2 High-end IDE/ATA, Low-end SCSI

10,000 3.0 High-end SCSI

12,000 2.5 High-end SCSI

15,000 2.0 Top-of-the-line SCSI


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The Hard Disk Drive :Access Time

Access Time =

Command Overhead Time

+ Seek Time

+ Settle Time

+ Latency


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The Hard Disk Drive :Command Overhead Time

Command Overheadrefers to the time that

elapses from when a command is given to the

hard disk until something actually startshappening to fulfill the command


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The Hard Disk Drive : Seek Time

Theseek timeof a hard disk measures the

amount of time required for the read/write

heads to move between tracks over thesurfaces of the platters.

h d i k i


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The Hard Disk Drive : Settle Time

Thesettle timespecification (sometimes

calledsettling time) refers to the amount of

time required, after the actuator has movedthe head assembly during a seek, for the heads

to stabilize sufficiently for the data to begin to

be read.

h d i k i


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The Hard Disk Drive : Latency

Latency is the time the drive must wait for the

correct sector to come around to where the

read/write heads are located after the actuatorassembly has completed its seek to the correct

track.

Th H d Di k D i


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The Hard Disk Drive : Latency(continued)

Spindle Speed(RPM)

Worst-Case Latency (FullRotation) (ms)

Average Latency (HalfRotation)(ms)

3,600 16.7 8.3

4,200 14.2 7.1

4,500 13.3 6.7

4,900 12.2 6.1

5,200 11.5 5.8

5,400 11.1 5.6

7,200 8.3 4.2

10,000 6.0 3.0

12,000 5.0 2.5

15,000 4.0 2.0


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The Hard Disk Drive : External Interface Types

Small Computer System Interface (SCSI)

Fibre Channel (FC)

Parallel ATAttachment (PATA) (also knownas IDE)

Serial ATA (SATA)

Serial Access SCSI (SAS)


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The Hard Disk Drive : Interface Comparison

Name Raw Bandwidth(Mbps)

TransferSpeeds (MB)

eSATA 3000 300

SATA 300 3000 300SATA 150 1500 150

PATA 133 1064 133

SAS 300 3000 300

SAS 150 1500 150Ultra320 SCSI 2560 320

FC over optic fiber 8000 1600

FC over copper 4000 400


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The RAID controller1. Normally configured in pairs for redundancy

and load balancing

2. RAID controller(s) have front-end(FE) &back-end(BE) ports. FE ports are attachedto the hosts while BE ports are connectedto the Disks3. Normally 2- 4 FE and BE ports each arepresent per controller

5. LUN masking & Multipathing support arealso implemented in the controller

4. Controllershave support for protocols for

connecting to the disks (normally FCAL)and to the hosts (FCAL, FCSW or iSCSI)


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The Battery-backed Cache1. This is high-speed memory (upto 16GB) for

holding data read from, or to be written to,the RAID groups in the disks

2. It can withstand power failure for a limitedperiod (36-72 hours) due to its batterybackup

3. May be mirrored in some arrays forreliability/ redundancy

5. Cache capacity and implementation isone of the major criteria in storage vendorselection

4. Divided into separate Read & Writecaches

6. Is required for improving read/write

performance


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The Hot Spare1. This is an additional disk drive in any storage

array configured to work as a standby driveduring normal operation but automaticallyreplaces any disk that becomes non-

operational.2. In case of an imminent disk failure the arraycontroller copies all data in the suspected diskto the hot spare, marks the hotspare as normaland the suspected disk as defective and

ready to be replaced.3. Hot spares may be, and normally are, more

than one.4. In the HP EVA series, there is no specific

hot spare.

C ti it


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Connectivity: Storage Area Networks

Host(s) are connected to the storage array(s)

via Storage Area Networks (SAN).

SANs facilitate : Block-level access to storage (the host sees

the allocated space as a local physical drive) Redundant host-storage paths with load

sharing and automatic failover Space in the same storage arraydistributed

amongmultiple hosts

St A N t k


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Storage Area Networks : Layers

A SAN consists of 3 layers:

Storage Layer consisting of all storage arrays

and tape drives Fabric layerconsisting of Fibre Channel

hubs,switches,directors,routers etc. and alloptical fiber cabling

Host layer consisting of all the hosts, host busadapters(HBAs) including Gigabit InterfaceConvertors(GBICs), their drivers andmultipathing software

St A N t k


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Storage Area Networks : Layers(contd.)

FC Switch

Host Layer

Fabric Layer

Storage Layer

FC Switch

Storage Array

St A N t k


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Storage Area Networks : Protocols

A SAN uses (originally) 2 protocols:

Fibre Channel Protocol which manages the

transport ofSCSI protocol messages betweenserver and storage across FC networkcomponents

SCSI Protocolwhich deals with commands forcommunication with the storage array

ib h l


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Fibre Channel :ActiveComponents

Hubs Any 2 ports can communicate at once Switches Any no. of pairs of ports can

communicate simultaneously Directors - A highly reliable switch withexpandable ports

Bridges, Gateways, DataRouters - Forprotocol conversion(like SCSI-FC, iSCSI-FC

etc.)

ib Ch l


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Fibre Channel :Cable Types

Fib Ch l


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Fibre Channel :LC,SC connectors

SubscriberConnector

(SC)

ucent Connector

(LC)

Fib Ch l


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Fibre Channel :Switch

Front view

Rear view

Fib Ch l


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Fibre Channel :Data Director

Fib Ch l


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Fibre Channel :Host Bus Adapter(HBA)

Fib Ch l


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Fibre Channel :Cabling & Switch

Fib Ch l


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Fibre Channel :Topologies

Point-to-Point Topology Arbitrated Loop Topology

Switched Fabric Topology

Fib Ch l


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Fibre Channel :Point-to-Point Topology

In Point-to-Point Topology, there is a directconnection between the Storage and theHost(Server) without any switch or hub

sharing the connection.

Storage connected in this fashion are alsocalled Direct Accessed Storage (DAS)

Fib Ch l


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Fibre Channel :Direct Attached Storage (DAS)

Storage Arrays directly connected to the hostsystem

BE-0

BE-1

DISK

DISK

DISK

DISK

FE-1

FE-0

LOOP

-1

LOOP

-0

Cache

RAIDController

HBA

Host-2

Fiber Channel

HBA

Host-1

Fiber Channel

Storage Array

Fib Ch l


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Fibre Channel :Multipathing Software

Fib Ch l


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Fibre Channel :Arbitrated LoopTopology

In Arbitrated Loop Topology, all devices areconnected in a loop using hubs

The protocol used in this topology is called

Fibre Channel Arbitrated Loop (FA-AL) Only one pair of devices in the loop getsthe entire bandwidth at any point of time.

A Maximum of 126 devices can be presentin a loop

Fibre Channel


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Fibre Channel :Switched FabricTopology

A switched fabric is a collection of switchestied together through inter-switch links tocreate a fabric of switches.

Each device in a fabric has an address

called a World Wide Name (WWN) thatshard-coded at the factory.This is a 64-bitnumber.

The protocol used in this topology is calledFibre Channel -Switched (FC-SW) protocol

Each pair of independent devices in thefabric gets the entire bandwidth at anypoint of time.

A Maximum of 64 million devices can be

present in a fabric.

Fibre Channel


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Fibre Channel :Basic FabricTopologies

Dual switch Loop of switches Meshed fabric

Star Core-edge

Fibre Channel :


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Fibre Channel :Dual Switch Topology

Fibre Channel :


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Fibre Channel :Loop-Of-Switches Topology

Fibre Channel :


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Fibre Channel :Meshed Fabric Topology

Fib Ch l


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Fibre Channel :Dual Meshed Fabric Topology

Fibre Channel


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Fibre Channel :Star Fabric Topology

St Ri H b id F b i


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Star Ring Hybrid FabricTopology

Fibre Channel :


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Fibre Channel :Core-Edge Topology

Fibre Channel :


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Fibre Channel :Terminology

FC Fibre Channel SAN Storage Area Network using SCSI

blocks over an FC-based network

Switched Fabric A collection of one or moreinterconnected FC switches SAN Fabric - A collection of all individual

Switched Fabrics in a SAN NAS Network Attached Storage using

CIFS(Common Internet File System) inWindows servers and NFS(Network FileSystem) in Unix servers to transfer files

Fibre Channel :


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Fibre Channel :Types of Switch Ports

G-Port Global port or unconnected port in aswitch

E-Port, T-Port Expansion orTrunk port for

inter-switch linking F-Port A switch (Fabric) port connected to a

host or storage FL-Port A switch (Fabric) port connected to

a hub(Loop) N-Port A Node(on a host or a storage array)port connected to a switch

NL-Port A Node(on a host or a storagearray) port connected to a hub(Loop)

Fibre Channel :


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Fibre Channel :FabricZoning

Zone Azone is a bunch of ports or WorldWide Name (WWN) addresses that are

isolated together into a group. Only memberswithin the group can see each other andcommunicate among themselves.

Zone set Azone setis a given group ofzones that, when activated,becomes the

current configuration that a particular switchor fabric uses to enforce the rules of who cantalk to whom. Only ONE zone set can beactive at any given time.

Zone Alias - Azone alias is just a friendly

Fibre Channel :


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Fibre Channel :Hard and Soft Zones

Soft Zones A soft zone is a zone describedin terms of World Wide Numbers(WWNs), i.e.,

devices connected to the fabric are allowedor disallowed access to one anotherdepending on their WWNs and irrespective ofwhich physical port they are connected to.

Hard Zone A hardzone is specified usingcombinations of domain id of the switch andthe number of the physical port in use.

Fibre Channel :


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Fibre Channel :LUN Security

LUN security is a storage array function tolock down which WWN(HBA) can see which

LUN on the array.

Also known as LUN Masking or SelectiveStorage Presentation(SSP)

LUN Security feature may or may not besupported by the Storage Array.

Storage Area Networks :


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Storage Area Networks : An example

FC Switch

FC SwitchFC Switch

Storage Array

Controller-1

Controller-2

FC Switch

50:06:0E:80:00:00:20:B2

50:06:0E:80:00:00:20:B1

50:06:0E:80:00:00:20:A2

50:06:0E:80:00:00:20:A1

10:00:00:00:00:00:87:65

10:00:00:00:00:00:12:34

10:00:00:00:00:00:43:21

10:00:00:00:00:00:56:78

Fabric-BFabric-A

UNIXWIN2K

Storage Area Networks :


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Storage Area Networks : An example (contd.)

Steps for configuring zones :

1. Set Domain ID in all switches in each fabric to makethem unique across fabrics.

2. Create an emptyzone setfor each fabric.

3. Create aliases for each WWN being attached to eachfabric

4. Create azone for eachHBA being connected to thefabric having one HBA alias/port and all storage ports

being provided access.

5. Add allzones created above to thezone set

6. Enable the zone set

7. Repeat above steps for other fabric

Storage Area Network


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Storage Area Network(SAN)

Storage Arrays connected to several hostsystems through a fiber channel(FC) switch

HBA

Host-2

HBA

Host-3

BE-0

BE-1

DISK

DISK

DISK

DISK

FE-1

FE-0

LOOP

-1

LOOP

-0

Cache

RAID

Controller

Storage ArrayHBA

Host-1

FC

switch

Network Attached Storage


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Network Attached Storage(NAS)

Storage Arrays connected to a host in turnsharing disk space

BE-0

BE-1

DISK

DISK

DISK

DISK

FE-1

FE-0

LOOP

-1

LOOP

-0

Cache

RAID

Controller

Storage ArrayHost sharingdisk space

HBA

HBA

Local

Area

Netw

ork

(LAN)


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SAN with NAS Gateway

Storage Arrays providing both SAN & NASconnectivity

HBA

Host-2

HBA

Host-3

BE-0

BE-1

DISK

DISK

DISK

DISK

FE-1

FE-0

LOOP

-1

LOOP

-0

Cache

RAID

Controller

Storage ArrayHBA

Host-1

FC

switch

LAN

Sharing diskspace

AS Gateway


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Thank you

Basic Training on Storage Technologies

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