Transcript Network-Attached Storage

Network-Attached Storage
Network-attached storage devices
• Attached to a local area
network, generally an
Ethernet-based network
environment
Network-attached storage devices
• Assigned their own IP address
Network-attached storage devices
• Allow for multiple computers to access data
Network-attached storage devices
• Able to comprise of single or multiple disks
and can utilize technologies such as RAID
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
RAID 0
• also referred to as disk striping
• data is written across multiple
drives simultaneously
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.
RAID 1
• also referred to as disk
mirroring
• creates an exact duplicate of
data written two separate
disks
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
RAID 5
combines the benefits of both RAID 0 and RAID 1
– speeds up the traditional transfer speed of data
– Provides fault tolerance
RAID 5
• uses a parity block interleaved across all the disks in
the array, in addition to striping the data across the
same drives.
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.
RAID continued
• The higher number does not signify a later or
better implementation of RAID
RAID 30 > RAID 10
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.
Images borrowed from:
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http://www.hdd-tool.com/raid/raid-0-features-advantage-and-disadvantage.htm
http://www.raids.co.uk/raid_0+1.htm
http://networkingpupil.blogspot.com/2010/10/nas_03.html
http://hothardware.com/Reviews/Thecus-N7700-Network-Attached-StorageServer/
http://www.nasreview.org/d-link-2-bay-network-attached-storage-enclosure-dns323/1
http://benchmarkreviews.com/index.php?option=com_content&task=view&id=58
&Itemid=70