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 +

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.

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