Transcript NAS / SAN Pres.

COEN 180
NAS / SAN
NAS
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Network Attached Storage (NAS)
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Each storage device has its own network interface.
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Filers: storage device that interfaces at the level of a
distributed file system.
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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
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Trends favoring NAS:
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Storage devices become more intelligent.
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Object based storage.
Storage devices become application aware.
NAS Advantages
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NAS devices are stand-alone.
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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
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Storage Area Networks
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Low costs
High transfer
Use a dedicated network.
SAN
SAN
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Host Layer
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Consists of storage servers and
components necessary to connect to SAN.
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HBA
Gigabit Interface Converter (GBIC) / Gigabit
Link Converter (GLC)
Host Bus Adapter Drivers
Cables
SAN
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Network Technology
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Fibre Channel
IP over Ethernet.
SAN
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Gigabit Interface Converter
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Converts to optical fiber.
Short wave:
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Laser frequency between 780 and 850 nm.
Used for distances between .5m and 500m.
Long wave:
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Laser frequency at 1300 nm.
Used for distances between 2 m and 10km.
Newer long-wave GBIC up to 100 km.
SAN
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Full duplex transmission
SAN
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Fabric Layer
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Contains the components necessary to
connect storage servers with storage
devices.
Hubs
Switches
Routers:
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Bridge between SCSI and Fibre Channel
Cables
SAN
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Storage Layer
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Monolithic
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Large with many disk drives
Modular
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Controller shelf plus single shelf of disks.
Add more shelves as needs grow.
SAN
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Storage Array Manufacturers
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Mainframe Class
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Hitachi
IBM
EMC
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Modular Class
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Hitachi
Compaq
Hewlett Packard
EMC
IBM
XIOtech
LSI Logic
Sun Microsystems
MTI
Fibre Channel
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Basic Fibre Channel Topologies
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Point to Point
Switched Fabric
Arbitrated Loop.
Fibre Channel
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Point-to-point
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Eliminates need to invest in fabric
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Other than cables.
Storage devices have more than one port
and can connect to as many servers as
they have ports.
Fibre Channel
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Arbitrated Loops
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Physically, consists of Fibre Channel hubs.
Internally, uses the FC-AL protocol.
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Fibre Channel Arbitrated Loop.
Can deal with 128 devices.
But looses performance much earlier.
Fibre Channel
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Switched Fabric
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Switches come in
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Modular class
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8 – 16 ports.
Multiple fans, power supply, etc.
Single controller component
 A single point of failure.
Director class
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32, 64, … ports
 Blades of ports.
Redundant components.
Fibre Channel
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Switched Fabric
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Run at 1Gb/sec
Run at 2Gb/sec
Will run at 10Gb/sec
Fibre Channel
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Switched Fabric
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Different Topologies
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Dual switches
Loop of switches
Meshed fabric
Star
Core-edge
switch
switch
Fibre Channel
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Fibre Channel Protocol
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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