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Latest trends and technologies in Storage Networking

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Examples Veritas Volume Manager, IBM Tivoli etc. Future of network storage SAN islands connected by IP networks Network Unified Storage (NUS) ... – PowerPoint PPT presentation

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Title: Latest trends and technologies in Storage Networking


1
Latest trends and technologies in Storage
Networking
  • By Gururaja Nittur
  • Advisor Dr. Chung E Wang
  • Second Reader Dr. Du Zhang

2
Scope of the Project
  • Study the new technologies in the storage
    networking arena
  • Fibre channel protocol
  • NAS, SAN and iSCSI
  • Storage Virtualization
  • High Availability
  • Demonstrate high availability by writing a
    DMP(Dynamic Multi Pathing) driver for Solaris

3
What is Storage Networking?
  • The practice of creating, installing,
    administering, or using networks whose primary
    purpose is the transfer of data between computer
    systems and storage elements and among storage
    elements

4
Why Storage Networks?
  • The total amount of data being stored doubles
    every year. Also, more than 90 of companies
    today would fail to survive a catastrophic data
    loss. Businesses face a mission-critical need to
    protect, access, and manage their ever-growing
    volume of storage assets
  • Explosive growth of business data
  • Internet and Multimedia
  • High Availability
  • Management complexity

5
Why Storage Networks? (Contd..)
6
Fibre Channel (FC)
  • A serial, high-speed data transfer technology
  • Open standard, defined by ANSI and OSI
  • Data rate upto 100 MB/sec. (200 MB/sec.
    full-duplex)
  • Supports most important higher protocols like IP,
    ATM, SCSI etc.
  • Does not have its own command set, but
    facilitates data transfers between individual FC
    devices.

7
Parallel Transmission
  • Set of data signals are sent simultaneously
    through 8, 16 or even more wires.
  • Problems with parallel transmission
  • data sent simultaneously over all the wires have
    to be received simultaneously as well
  • Total time tdt
  • t - time taken for the signals to reach
    receiver
  • dt additional delay due to hardware
    inconsistencies
  • dt increases with cable length causing lesser
    frequency
  • Example - SCSI
  • Bus length limitations
  • Max bus speed is limited (40 MB/sec in Ultra
    SCSI)
  • Limited device count

8
Serial Transmission
  • Serial transmission uses single cable
  • All signals are delayed the same and arrive at
    the receiver in the same order in which they were
    sent.
  • Higher bus length
  • Examples
  • SSA (Serial Storage Architecture by IBM)
  • Fibre Channel

9
Current Technology
  • DAS using SCSI

10
Emerging Technologies
  • Network Attached Storage (NAS)
  • Storage Area Networks (SAN)
  • Storage over IP (iSCSI)

11
Network Attached Storage
12
Network Attached Storage
  • Storage device will have a built-in network
    interface
  • NAS unit can be plugged directly into the network
    to allow quick and easy access
  • Standard network protocols such as CIFS and NFS
    can be used to share data

13
Network Attached Storage
  • NAS engine is usually SCSI for low-end systems
    for cost reasons and Fibre Channel for the
    enterprise systems
  • NAS is easy to install and relatively easy to
    maintain
  • Network is used exclusively for data transfer
    causing additional overhead
  • Backup using LAN is really a overhead

14
Storage Area Networks
15
Storage Area Networks
  • As much as 60 of the traffic on a std corporate
    network is made up of housekeeping actions like
    Backup
  • Storage Area Network has been fuelled
    significantly by the desire to get this
    housekeeping off the network
  • Primary interface for SAN infrastructure is Fibre
    Channel

16
Storage Area Networks
  • SAN provides excellent performance and easier
    management
  • SAN implementations are expensive due to hardware
    costs
  • Better resource sharing could make up for the
    initial investment
  • SAN is very flexible in that more storage and
    servers can be added easily

17
iSCSI
  • Motivation
  • GB Ethernet
  • iSCSI is a draft standard protocol to encapsulate
    SCSI commands into TCP/IP packets
  • Can be used to build IP based SANs

18
Storage Virtualization
  • The research firm Gartner Group estimated that
    80 of the storage costs is used up for managing
    the installed storage
  • Switch and array management becomes very
    difficult with increased storage hardware
  • Virtualization provides a logical view and eases
    management.
  • Examples Veritas Volume Manager, IBM Tivoli
    etc.

19
Future of network storage
  • SAN islands connected by IP networks
  • Network Unified Storage (NUS)
  • NAS SAN on GB Ethernet networks

20
High Availability
Single Point Failure
Multi Pathing
21
Dynamic Multi Pathing
  • Increased disk availability
  • Load balancing
  • Identifies disks uniquely from different hosts

22
Dynamic Multi Pathing
23
Implementation Details
  • Scan the disks listed in /dev/rdsk
  • If no UUID is present, generate a unique UUID and
    stamp it in the disks private region
  • Add this device to a hash table hashed on UUID
  • Load this table to the kernel and write the
    ioctls to update this info
  • Use an algorithm (Currently round robin) to
    efficiently load balance the I/O requests.
  • If a path is bad for more than five I/O attempts,
    mark it bad and do not use it for path selection.

24
Implementation Details
  • User code
  • Read /dev/rdsk folder and generate a hashed list
    of available disks
  • Load this list to kernel. Also provide APIs to
    push newly added/removed disks.
  • Kernel code
  • Filter driver to choose the best path
  • ioctls to do the following
  • LOAD_DISKS
  • NEW_DISK
  • MODIFY_DISK
  • GET_DISK_HANDLE

25
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