Cisco Press - Introduction To Storage Area Networking Technologies (Slides).doc

introduction to storagenetworkingsession cdc-101 agenda storage basics and terms introduction to sans san connectivityfibre channel san applications sancurrent developments cisco storage networking partnerships storage basics and termsserver attached storage server centric modelall storagebehind server cpu server data access is file system andplatform dependentserver cpu must handle not onlyuser i/o requests, but also:user database inquiriesuser file/print servingdata integrity checkingcommunication with other devices clients lan burdened with disk i/o traffic i/o channel simply stated, it is the technology which resides betweena computer and the device used to store its data this relationship can exist either internal to thecomputer enclosure or can extend to externalstorage devicesstorage device is only accessible by attached host computerexamples are scsi, fibre channel, escon i/o controller external i/o internal i/o network attached storage (nas) dedicated (thin) file server,optimized for the specificpurpose of providing networkaccessible storage to serversover the lan server nas attaches directly to network capable of storage partitioning uses network file systemprotocols such as nfs or cifs suitable for applicationsinvolving file serving/sharing file i/o redundant array of inexpensive disks (raid) fault-tolerant grouping ofdisks that server views as a single disk volumecombination of striping,mirroring, and parity checking self-contained, manageableunit of storagemanagement: one file systemacross entire virtual disk raid delivers capacity,performance, reliability,and availability benefitsjust a bunch of disks (jbod)drives are independantlyattached to i/o channelscalable, but requires servers to managemultiple volumesno protection in theevent of drive failuredrives share common power supplies andphysical chassissmall computer system interface (scsi)parallel interface i/o technology maximum cable run length is 25 meters speeds up to 320 mb/sec (ultra scsi-3 on 16-bit wide bus) maximum of 16 (i/o controller + devices)scsi devices per busevolving standard: scsi-1 scsi-2 scsi-3 scsi-4 scalability and distance limitations rule out support of largescale storage systems requiring disaster recovery scsi terminator on chain link portadapter enterprise system connection (escon) originally developed specifically foruse between ibm s/390 servers and ibm s/390storage or other peripheral devicesstandard widely supported in othervendors storage productstransmits over fiber optic cable max distance of 43 km max speed of 17 mb/sec introduction of escon directors (switches) allow dynamic connectioncapabilities; original technology wasstatic point-to-point storage basics and terms introduction to sans san connectivityfibre channel san applications sancurrent developments cisco storage networking partnerships agenda introduction to sanssan: what is it?lan (packets) san (blocks) storage devicessan architectural model gartner group,1999 gartner group propose that a true san consists of a“connectivity” portion (device oriented) and a “value”portion (provides san services) “connectivity” is provided by technologies such asfibre channel devices, escon, scsi “value” is delivered by software, functions like zoning,masking, outboard backup, pooling, file sharing gartner group symposium, cannes, france, november 1999 san componentsservers with host bus adapters (hbas) storage systems raid jbod tape optical disk hubs switches san managementsoftware the promises of sanmassively extended scalabilitygreatly enhanced deviceconnectivity storage consolidation/centralized data management lan-free, centralized backup serverless (active-fabric) backupserver clustering heterogeneous data sharingdisaster recoveryremotemirroring sans: scalability and performancestorage expansion no impact on servers server expansion no impact on storage load balancing active parallel paths bandwidth on demand robust topology sans: high availability multiple levels of redundancy areconfigurable throughout data path (dualhbas, redundant fabric, server clusters) multiple access paths allow failover clusterconfigurations de-coupling of storage from applicationsallows it to be managed independentlydata vaulting and disaster recoveryconfigurations can address loss ofservice due to site failuressan and nasdifferences?san and naswhen to use what? nas and san solutions solve different application storage requirements san is appropriate for dbms (oltp) storage and most application scenarios nas is appropriate for file serving andfile sharing applications introduction to sanssummary sans fully exploit high-performance,high connectivity network technologies expand easily to keep pace with fastgrowing storage needs allow any server to access any data help centralize management of storage resources reduce total cost of ownership agenda storage basics and terms introduction to sans san connectivityfibre channel san applications sancurrent developments cisco storage networking partnerships san connectivityfibre channelwhat is fibre channel?american national standards institute (ansi)standard drafted in 1988 combines the benefits of both channel and network technologies scsi and ip are the primary upper layer protocolscommercially available on fibre channel benefits of mapping scsi onto fibre channelinclude:faster speed over parallel scsiability to connect more storage devices togethergreater distances allowed between storage devices operates over copper (twisted pair) or glass(fiber optic) cable fibre channel offersmultiple protocol support(todaymainly ip and scsi) networking (bridging and switching)capability and functionality heterogeneous interconnect speed: 1 gbps today, 2 gbps in 2001 (readynow on hbas); 10 gbps in near future (2002) boasts: bandwidth, availability, reliability,integrity, and scalability fibre channelbest of both worldsi/o channel data block-based closedstructuredhigh performanceerror free large data transferhardware intensivenetwork packet-based open, unstructurederror-free secondarypeer to peer data, voice, video software intensive fibre channelbest of both worlds!fibre channelport types n port: node ports used for connecting peripheralstorage devices to switch fabric or for point-to-pointconfigurationsf port: fabric ports reside on switches and allowconnection of storage peripherals (n port devices)l port: loop ports are used in arbitrated loopconfigurations to build storage peripheral networkswithout fc switches; these ports often also have n portcapabilities and are called nl ports e port: expansion ports are essentially trunk ports usedto connect two fibre channel switches g port: a generic port capable of operating as either ane or f port; if also capable of acting in an l portcapacityknown as a gl port point-to-pointarbitrated loop switched fabric dedicated connection between n port fibre channel devices all link bandwidth fibre channel topologiespoint-to-pointnnis dedicated to communication between the two nodessuitable for small scale scenarios when storagedevices are dedicated to file servers arbitrated loop (fc-al)tx of each node is connected to the rx of the next node until a closed loop is formed maximum bandwidth: 100 mb/sec. (shared amongstall nodes on loop) 126 nodes max on loop not a token passing schemeno limit on how long a devicemay retain controloperational sequence: arbitrate for control of loopopen channel to targettransfer data closenumber of nodes on loop doesdirectly affect performance max nodes = 16 million (24 bits) max bandwidth = 100 mb/sec nodes (n ports) connect tofabric (f ports) end-to-end connection managed by n ports switching and addressinghandled by fabric e-port provides trunkconnectivity to anotherfibre channel switch switched fabriccombining loops and fabricsnode e fabrics can connect multiple arbitrated loops each loop can only contain a single fabric/loop (fl) port nodes on the loops can communicate publicly with otherdevices reachable via fabric; alternatively, nodes can beprivate, allowing them to only communicate with otherdevices within their respective loop fibre channel zoning zoning arranges fc connected devices intological groups operation zone members can only see members in same zone zones are configured dynamically devices can belong to multiple zones zoning is supported on most fibre channelfabric switches benefits secured device access allows for operating systemco-existence fibre channel zoning examplenodes a, b, and c can communicate with each other in zone a nodes c, d, and e can communicate with each other in zone b