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1、Introduction to Storage Area Networks(SAN),SAN-1501,Session Agenda,Storage BasicsThe What Fibre Channel Basics and the How.Where to go from here,Main Topics for Today,Storage Basics,Storage Basics,Storage componentsHost bus adapterDisks,JBODs,RAID,storage arraysStorage topologiesDAS,NAS,and SANStora
2、ge protocolsSCSIStorage transport protocolsFibre Channel(FC),FCIP,iSCSI,Storage Components,Host Storage Components,Host bus adapter(HBA)Hardware resident on host serverConnection interface to disk subsystemConnection methodCopperOptical,Data Storage Components,Fundamental unit for data storageDisk d
3、rive typesParallel SCSIFibre channelAdvanced Technology Attachment ATA)or Integrated Drive Electronics(IDE)Serial ATA(SATA)OtherTape drives,I/O DevicesDisk Drives,Storage Interconnects,Connecting Hosts to Storage,Parallel SCSI copper interconnectsOptical direct connectFibre Channel switch,The SCSI I
4、/O ChannelStarting Point,SCSI I/O Channel provides half-duplex pipe for SCSI command,data,and statusSCSI I/O channel can be internal or external to hostMultiple SCSI I/O channels can exist within hostA network approach can scale the I/O channel in many areas(length,devices,throughput),NIC Adapter,SC
5、SI Adapter,NIC Driver,TCP/IP Stack,Adapter Driver,SCSI Generic,Block Device,File System,Applications,Half-DuplexI/O Channel,SCSI,SCSI,SCSI,SCSIInitiator,SCSITarget,SCSI,I/O Channel,Target 2,ChannelController,Host(Initiator),Target 1,The Parallel SCSI I/O Channel,The SCSI Channel is used to transmit
6、SCSI commands,data,and statusMultiple devices can exist on the channel each playing the role of SCSI initiator or SCSI targetMost common channel is the basic parallel SCSI bus which can be internal or external to a hostParallel SCSI Specifications:Up to 25m bus length Shared channel bandwidth upto 3
7、20MBps Up to 16 devices per SCSI bus Half-duplex operation,SCSI,Target,ChannelController,Host(Initiator),NetworkedI/O Channel,Initiator,Networking the I/O Channel,Same SCSI protocol carried over a network transport via serial implementationTransport must not jeopardize SCSI payload(security,integrit
8、y,latency)Two primary transports to choose from today,namely IP and Fibre ChannelA networked I/O channel allows for multiple improvements:Distance limitations greatly increased Dedicated bandwidth(not shared)High#of addressable devices Bandwidth increase(including link bundling),Network,Fibre Channe
9、lFabric,SCSI,Target,EthernetNIC,Host System,Initiator,Fibre Channel I/O Networking,Very common method for networking SCSIFibre Channel provides high speed transport for SCSI payload Fibre Channel overcomes many shortcomings of Parallel I/O including:Addressing for up to 16 million nodes Loop(shared)
10、and fabric(switched)transport Host speeds of 100 to 400 MBps(1-4 Gbps)Segments of up to 10km(without extenders)Support for multiple protocolsCombines best attributes of a channel and a network together,IP I/O Channel Networking,IP access to open systems iSCSI and Fibre Channel storageiSCSI driver is
11、 loaded onto hosts on Ethernet networkAble to consolidate servers via iSCSI onto existing storage arrays Able to build Ethernet-based SANs using iSCSI arraysStorage can be mapped from iSCSI to Fibre Channel,iSCSI-EnabledHost(Initiator),iSCSI Appliance(Target),StoragePool(Target),iSCSIGateway,IPNetwo
12、rk,FCFabric,FC HBA Attached Host(Initiator),iSCSI,EthernetNIC,SCSI,Storage Subsystems,Just a bunch of disks(JBOD)Storage arraysRedundant array of independent disks(RAID),Simple Storage Systems,I/O DevicesJBODs,ServerWith SCSI,ServerWith Fibre ChannelArbitrated Loop(FC-AL),TRGT 0,TRGT 2,TRGT 1,TRGT 3
13、,TRGT 4,SCSI JBOD,FC-AL,TRGT 3,TRGT 4,TRGT 5,FC-AL JBOD,SCSI BUS,TRGT 0,TRGT 1,TRGT 2,SCSI CABLE,FC CABLE,Large Storage Systems Bus Type,I/O DevicesIntelligent Storage Arrays,X BUS,Y BUS,Host Bus Adapters,Host Bus Adapters,Disk Drives,Disk Drives,Host ChannelConnections,Dual-ProcessorChannel Directo
14、r,Cache,System Bus,Dual-ProcessorDisk Director,Disks,CD,CD,CD,CD,Cache,DD,DD,DD,DD,Large Storage Systems Switched Type,Host ChannelConnections,Dual-ProcessorChannel Connectors,SwitchedBackplane,Dual-ProcessorDisk Connectors,Disks,Host Bus Adapters,Host Bus Adapters,Cache,Disk Drives,Disk Drives,DD,D
15、D,DD,DD,CD,CD,CD,CD,I/O DevicesIntelligent Storage Arrays,Logical Arrays of Storage,Redundant Array of Independent Disks(RAID)Word coined by researchers at University of California,Berkeley in 1987A method to inexpensively put together a set of physical hard drives into an arrayProvides fault tolera
16、nce by mirroring or parity operationsRAID can be performed using hardware or using host based software,RAID,Types of RAID,RAID 0:StrippingFor performance and size,two or more hard disks are concatenated together to form a larger volume RAID 1:MirroringFor reliability and availability RAID 3:Error De
17、tectionFor reliability,availability of data using using a dedicated parity driveRAID 5:Error CorrectionFor reliability,availability of both data and parity,RAID 0:Striping,Data is segmented and split across multiple spindlesI/O benefitsShort reads and writes,easily handles multiple simultaneous read
18、sLong reads and writes,single operations split and processed in parallelRedundancynoneCostgood(no extra hardware),RAID 1:Mirroring,Data is duplicated on multiple spindlesI/O benefitsShort and long reads with shorter latencyShort and long writes slower due to multiple writesRedundancygoodCostneed dou
19、ble the amount of disks,RAID 0+1:,Data is striped and duplicated on multiple spindlesI/O benefitsShort and long reads with shorter latencyShort and long writes faster as writes are spread across multiple spindlesRedundancygoodCostneed double the amount of disks,RAID 1+0:,Data is duplicated and strip
20、ed on multiple spindlesI/O benefitsLess downtime than RAID 0+1RedundancygoodCostneed double the amount of disks,RAID 5:Error Correcting,Data protection using ECC(Error Correction Control)parity spread over all drivesI/O benefitsShort and long reads at normal speedsShort and long writes slower due to
21、 parity calculationsRedundancybetter than RAID3Costneeds only one extra disk for an entire logical disk,Storage Topologies,IP Front-End Network,SAN Back-End Network,SAN,IPNetwork,Storage Topologies,Host to Host Application to file system Client to Server NFS,SMB,CIFS,NCP NAS,WAFS,Host to Storage Fil
22、e system to Device Program to Device SCSI,IDE,NTFS,FAT SAN,Direct Attached Storage(DAS),Storage is captive behind the server,limited mobilityLimited scalability due to limited devicesNo efficient storage sharing possibleCostly to scale;complex to manage,FC,Clients,Direct Attached Storage,Application
23、 Servers,Win2k,Linux,Unix,Unix,Tape,FC,Linux,Win2k,SCSI,LAN,Network Attached Storage(NAS),Storage is accessed at a file level via NFS or CIFSStorage is accessed over an IP network Storage devices can be shared between serversFiles can be shared between usersTCP can be tuned to optimize for file tran
24、sport,ApplicationServers,NAS AppliancesorNAS Head Ends,Generic,Generic,NAS=Optimized for File I/O,Win2k,Linux,Unix,LAN,Storage Area Network(SAN),Storage is accessed at a block-level via SCSIHigh performance interconnect providing high I/O throughputLower TCO relative to direct attached storage,stora
25、ge can be sharedLimited vendor interoperability Complex management,Separation of Storage from the Server,Servers,BlockStorageDevices,Fibre Channel SAN,Clients,LAN,iSCSI Storage Network,Storage is accessed at a block-level via iSCSIGood performance via standard Ethernet NICEnhanced performance with T
26、CP Offload Engine(TOE)Lower TCO relative to direct Fibre Channel HBA/FabricStandards based Complex management,iSCSI-EnabledHosts(Initiators),iSCSI Appliance(Target),StoragePool(Target),iSCSIGateway,IPNetwork,FCFabric,FC HBA Attached Host(Initiator),DAS,SAN,iSCSI,NAS Comparison,Host/Server,StorageTra
27、nsport,StorageMedia,Computer System,Computer System,Computer System,Computer System,Block I/O,File I/O,Wide Area File Services(WAFS),WAFS Provides File Services Between a Remote Client and a Centralized Server,Storage Protocols,Small Computer System InterfaceSCSI,SCSI is a standard that defines an i
28、nterface between an initiator(usually a computer)and a target(usually a storage device such as a hard disk)Interface refers to connectors,cables,electrical signals,optical signals and the command protocol that allow initiators and targets to communicateLogical Unit Number(LUN):A 64-bit field within
29、SCSI that identifies the Logically addressable Unit within a target SCSI device,SCSI Command Protocol,SCSI command protocol is the de facto standard that is used extensively in high-performance storage applicationsThe command part of SCSI can be:Transported over a Fibre Channel storage area networkE
30、ncapsulated in IP and carried across IP networksTo understand the finer points involved with transporting SCSI across a network with FC or Ethernet,the basics of SCSI must be well understood,Standards,SCSI has evolved since it was introduced as SASI in 1979 by Shugart Associates it was approved as a
31、 standard by ANSI in 1986 and is now referred to as SCSI-1SCSI-2 was approved by X3 in 1990 and by ANSI in 1994SCSI-3 refers to a collection of standards,each of which defines a very specific part of SCSI:physical interface,transport interface,command interface,architecture model,programming interfa
32、ce,etc.Also known as SCSI Architecture Model 3(SAM-3),SCSI Architecture Model,SAN,SCSI I/O Channel,The SCSI I/O Transaction,The SCSI protocol forms the basis of an I/O transactionThe channel provides connectivity between communicating devices in a SCSI transactionThe following shows two sample SCSI
33、exchanges:,Host(Initiator),Disk(Target),SCSI I/O Channel,Disk(Target),Host(Initiator),SCSI READ OPERATION,SCSI WRITE OPERATION,SCSI Commands,Data transferREAD,WRITECommands used in boot/discovery:REPORT LUNS INQUIRY TEST UNIT READY,SCSI Read,Send SCSI Cmd issued by initiator the command sent is READ
34、;SCSI Command Received by target;Data transfers occur during the working phase between initiator and target;Send Command Complete is returned by the target;Command Complete Received by target.,SCSI Write,Send SCSI Cmd issued by initiatorthe command sent is WRITE;SCSI command received by target;Targe
35、t returns TRGT-RDY;Initiator receives TRGT-RDY;Data transfers occur during the working phase between initiator and target;Status complete is returned by the target;Status complete received by initiator,Storage Transport Protocols,Protocols used to transport SCSI Command and DataParallel SCSIFibre Ch
36、annelFCIPiSCSI,Storage Protocols,Protocol and Transport Stack,Parallel SCSIInterfaces,Fibre Channel,Ethernet,IP,TCP,Parallel SCSIInterfaces,Fibre Channel,iSCSI,SCSI Commands,Data,and Status,SCSI Block Commands,SCSI StreamCommands,Other SCSI Commands,SCSI Applications(File Systems,Databases),FCIP,Fib
37、re Channel,SCSI,I/O Channel,Target 2,ChannelController,Host(Initiator),Target 1,The Parallel SCSI I/O Channel,The SCSI Channel is used to transmit SCSI commands,data,and statusMultiple devices can exist on the channel each playing the role of SCSI initiator or SCSI targetMost common channel is the b
38、asic parallel SCSI bus which can be internal or external to a hostParallel SCSI Specifications:Up to 25m bus length Shared channel bandwidth upto 320MBps Up to 16 devices per SCSI bus Half-duplex operation,Storage Protocols,Parallel SCSIInterfaces,Fibre Channel,Ethernet,IP,TCP,Parallel SCSIInterface
39、s,Fibre Channel,iSCSI,SCSI Commands,Data,and Status,SCSI Block Commands,SCSI StreamCommands,Other SCSI Commands,SCSI Applications(File Systems,Databases),FCIP,Fibre Channel,Fibre Channel Protocol and Transport Stack,What Is It?Fibre Channel,ChannelsConnection servicePhysical circuitsReliable transfe
40、rsHigh speedLow latencyShort distanceHardware intense,NetworksConnectionlessLogical circuitsUnreliable transfersHigh connectivityHigher latencyLonger distanceSoftware intense,Fibre ChannelCircuit and packet switchedReliable transfersHigh data integrityHigh data ratesLow latencyHigh connectivityLong
41、distance,FICON,FC SingleByte CommandSets,IP,Link Encapsulation(FC-LE),ULP(Upper Level Protocol)(sample there are more),SCSI-3,SCSI-3 Mapping(SCSI-FCP),FC-4,SNMP Mapping(FC-SNMP),FC-3,Common Services,FC-0,FC-1,FC-2,Fibre Channel Physical&Signaling Interface(FC-PH,FC-PH2,FC-PH3),Physical Interface,Enc
42、ode/Decode,Framing Protocol,FC-AL,FC-AL-2,FC-SW-2,Copper,Optical,8B/10B Encoding,Fibre Channel Protocol Architecture,Fibre Channel Mapping,SCSI Architecture to Fibre Channel Mapping,FCP GoesHere(FC-4),FC-3FC-2FC-ALFC-1FC-0,Fibre Channel Functions,FC-0Defines the physical interface characteristicsSig
43、naling rates,cables,connectors,distance capabilities,etc.FC-1Defines how characters are encoded/decoded for transmissionTransmission characters are given desirable charactersFC-2 Defines how information is transportedFrames,sequences,exchanges,login sessionsFC-3 Place holder for future functionsFC-4
44、 Defines how different protocols are mapped to use Fibre ChannelSCSI,IP,Virtual Interface architecture,FICON,others,Structure Is Divided into 5 Levels of Functionality,Fibre Channel FC-2 Hierarchy,Multiple exchanges are initiated between initiators(hosts)and targets(disks)Each exchange consists of o
45、ne or more bi-directional sequencesEach sequence consists of one or more framesFor the SCSI3 ULP,each exchange maps to a SCSI command,Idles*,SOF,Frame Header,Data Field,CRC,EOF,Idles*,General FC-2 Frame Format,Frame Content,0-528 Transmission Word,(4),(4),(0-2112),(24),(4),Fibre Channel Frame Format
46、,All FC-2 frames follow the general frame format as shown belowIdles are Ordered Sets used for synchronization and basic signalingSOF Start-of-Frame,EOF End-of-Frame,*6 Idle words(24 bytes)requires by TX 2 Idle words(8 bytes)guaranteed to RX,Fibre Channel Storage Area Network(SAN),Host,Storage,Stora
47、ge,Host,Storage Protocols,FCIP Protocol and Transport Stack,Parallel SCSIInterfaces,Fibre Channel,Ethernet,IP,TCP,Parallel SCSIInterfaces,Fibre Channel,iSCSI,SCSI Commands,Data,and Status,SCSI Block Commands,SCSI StreamCommands,Other SCSI Commands,SCSI Applications(File Systems,Databases),FCIP,Fibre
48、 Channel,IP,Storage Protocols-FCIP,Primary use is for Storage-to-Storage connectivity via an IP WAN/MANThe FCIP Link carries encapsulated fibre channel traffic between Link End Points over an IP network by using TCP on port 3225The result is a virtual Inter Switch Link(ISL)between FC FabricsFC frame
49、 not changed,TCP,FCIP,FC,SCSI,Data,FCIP Frame Format,FCIP SAN Interconnect,IP,Virtual ISL,FCIP Link,Storage,Storage,Host,Host,Storage Protocols,iSCSI Protocol and Transport Stack,Parallel SCSIInterfaces,Fibre Channel,Ethernet,IP,TCP,Parallel SCSIInterfaces,Fibre Channel,iSCSI,SCSI Commands,Data,and
50、Status,SCSI Block Commands,SCSI StreamCommands,Other SCSI Commands,SCSI Applications(File Systems,Databases),FCIP,Fibre Channel,Storage Protocols,Primary use is for Host-to-Storage connectivity via an IP LANSCSI command and data are encapsulated into iSCSI by adding a special headeriSCSI data is enc
