COEN 180 NAS / SAN
Storage Trends • Storage Trends: • Money is spend on administration Morris, Truskowski: The evolution of storage systems, IBM Systems Journal, Vol. 42(2)
Direct Attached, SAN, NAS Storage Morris, Truskowski: The evolution of storage systems, IBM Systems Journal, Vol. 42(2)
Direct Attached, SAN, NAS Storage Morris, Truskowski: The evolution of storage systems, IBM Systems Journal, Vol. 42(2)
Direct Attached, SAN, NAS Storage Morris, Truskowski: The evolution of storage systems, IBM Systems Journal, Vol. 42(2)
Direct Attached, SAN, NAS Storage Morris, Truskowski: The evolution of storage systems, IBM Systems Journal, Vol. 42(2)
NAS • Network Attached Storage (NAS) • Each storage device has its own network interface. • Filers: storage device that interfaces at the level of a distributed file system. • Network File System: NFS (Unix) • Common Internet File System CFIS (MS Win) • Flexible. • Sharing of storage. • Vulnerable. • Sharing network makes megatasks such as back-up difficult.
NAS
NAS • Trends favoring NAS: • Storage devices become more intelligent. • Object based storage. • Storage devices become application aware.
NAS Advantages • NAS devices are stand-alone. • Have their own OS, networking, integrated hardware, and software. • NAS devices offer shared storage, accessible from a number of platforms. • NAS devices can easily be added on to an existing network.
SAN • Storage Area Networks • Low costs • High transfer • Use a dedicated network.
SAN
SAN • Host Layer • Consists of storage servers and components necessary to connect to SAN. • HBA • Gigabit Interface Converter (GBIC) / Gigabit Link Converter (GLC) • Host Bus Adapter Drivers • Cables
SAN • Network Technology • Fibre Channel • IP over Ethernet.
SAN • Gigabit Interface Converter • Converts to optical fiber. • Short wave: • Laser frequency between 780 and 850 nm. • Used for distances between .5m and 500m. • Long wave: • Laser frequency at 1300 nm. • Used for distances between 2 m and 10km. • Newer long-wave GBIC up to 100 km.
SAN • Full duplex transmission
SAN • Fabric Layer • Contains the components necessary to connect storage servers with storage devices. • Hubs • Switches • Routers: • Bridge between SCSI and Fibre Channel • Cables
SAN • Storage Layer • Monolithic • Large with many disk drives • Modular • Controller shelf plus single shelf of disks. • Add more shelves as needs grow.
SAN • Storage Array Manufacturers • Mainframe Class • Hitachi • IBM • EMC • Modular Class • Hitachi • Compaq • Hewlett Packard • EMC • IBM • XIOtech • LSI Logic • Sun Microsystems • MTI
Fibre Channel • Basic Fibre Channel Topologies • Point to Point • Switched Fabric • Arbitrated Loop.
Fibre Channel • Point-to-point • Eliminates need to invest in fabric • Other than cables. • Storage devices have more than one port and can connect to as many servers as they have ports.
Fibre Channel • Arbitrated Loops • Physically, consists of Fibre Channel hubs. • Internally, uses the FC-AL protocol. • Fibre Channel Arbitrated Loop. • Can deal with 128 devices. • But looses performance much earlier.
Fibre Channel • Switched Fabric • Switches come in • Modular class • 8 – 16 ports. • Multiple fans, power supply, etc. • Single controller component • A single point of failure. • Director class • 32, 64, … ports • Blades of ports. • Redundant components.
Fibre Channel • Switched Fabric • Run at 1Gb/sec • Run at 2Gb/sec • Will run at 10Gb/sec
Fibre Channel • Switched Fabric • Different Topologies • Dual switches • Loop of switches • Meshed fabric • Star • Core-edge switch switch
Fibre Channel • Fibre Channel Protocol • FC-4: Upper Layer Protocol Interface supports VI, IP, and most importantly, serial SCSI-3 (FCP). The task of FCP is to make fibre channel devices appear as standard SCSI devices to each other. This strategy avoids OS modifications in the storage servers. • FC-3: Common Services, is currently under development and will contain such services as striping a transmission over several ports, hunt groups that allow more than one port to respond to the same alias address (in order to decrease chances of hitting on a busy port), and multicasting. • FC-2: Data Delivery codifies framing, flow control and service class. A fibre channel frame consists of 32B frame meta data framing a 2112 B data field that contains up to 2048B payload. The fiber channel service classes allow either an in effect a virtual physical connection (class 1), or packet switched connections with (class 1) or without (class 2) acknowledgments. • FC-1: Ordered sets / byte encoding. • FC-0: Physical interface (optical/electrical, cable plant).
Fibre Channel
SAN /NAS
