Network-Attached Storage

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Network-Attached Storage
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Network-attached storage devices

• Attached to a local area network, generally an
  Ethernet-based network environment

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Network-attached storage devices

• Assigned their own IP address

192.168.221.50
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Network-attached storage devices

• Allow for multiple computers to access data

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Network-attached storage devices

• Able to comprise of single or multiple disks and
  can utilize technologies such as RAID

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Network-attached storage devices

• Comprises of
• hard disk storage
• can include multi-disk and/or RAID systems
• software for configuring and file locations
  mapping to the network-attached device

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Redundant Array of Independent Disks

• also known as RAID
• a way of combining the storage capabilities of
  more than one hard disk for enhanced purposes,
  including
• an increase in performance
• fault tolerance.
• Several different configurations of RAID
• Most Common include RAID 0, RAID 1, and RAID 5

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RAID 0

• also referred to as disk striping
• data is written across multiple drives
  simultaneously

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RAID 0

• Benefits
• speeds up the traditional transfer speed of data
• Disadvantages
• provides no fault tolerance
• Should a single drive in a RAID 0 array fail, all
  content is lost as content is distributed in bits
  across multiple drives.

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RAID 1

• also referred to as disk mirroring
• creates an exact duplicate of data written two
  separate disks

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RAID 1

• Benefits
• Provides fault tolerance
• In the event of a disk failure, RAID 1 allows for
  the quickest and easiest method of data retrieval
  by switching to the backup or alternative drive.
• Disadvantages
• is costly because all storage needs are doubled
  to account for the space redundancy, and there is
  no increase in data access

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RAID 5

• combines the benefits of both RAID 0 and RAID 1
• speeds up the traditional transfer speed of data
• Provides fault tolerance

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RAID 5

• uses a parity block interleaved across all the
  disks in the array, in addition to striping the
  data across the same drives.

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Parity

• is done by storing an extra bit with and based
  on each byte in memory.
• When a byte is accessed, the validity of the
  parity bit is checked.

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RAID continued

• The higher number does not signify a later or
  better implementation of RAID
• RAID 30 gt RAID 10

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RAID continued

• However, certain number may signify the
  implementation of two RAID structure such as RAID
  10 or RAID 01, which are combinations of RAID 1
  and RAID 0.

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Images borrowed from

• http//www.hdd-tool.com/raid/raid-0-features-advan
  tage-and-disadvantage.htm
• http//www.raids.co.uk/raid_01.htm
• http//networkingpupil.blogspot.com/2010/10/nas_03
  .html
• http//hothardware.com/Reviews/Thecus-N7700-Networ
  k-Attached-Storage-Server/
• http//www.nasreview.org/d-link-2-bay-network-atta
  ched-storage-enclosure-dns-323/1
• http//benchmarkreviews.com/index.php?optioncom_c
  ontenttaskviewid58Itemid70