|Features||RAID 0||RAID 1||RAID 1E||RAID 5||RAID 5EE|
|Minimum # Drives||2||2||3||3||4|
|Data Protection||No Protection||Single-drive failure||Single-drive failure||Single-drive failure||Single-drive failure|
|Read Performance (degraded)||N/A||Medium||High||Low||Low|
|Write Performance (degraded)||N/A||High||High||Low||Low|
|Capacity Utilization||100%||50%||50%||67% - 94%||50% - 88%|
|Typical Applications||High End Workstations, data logging, real-time rendering, very transitory data||Operating System, transaction databases||Operating system, transaction databases||Data warehousing, web serving, archiving||Data warehousing, web serving, archiving|
|Features||RAID 6||RAID 10||RAID 50||RAID 60|
|Minimum # Drives||4||4||6||8|
|Data Protection||Two-drive failure||Up to one disk failure in each sub-array||Up to one disk failure in each sub-array||Up to two disk failure in each sub-array|
|Read Performance (degraded)||Low||High||Medium||Medium|
|Write Performance (degraded)||Low||High||Medium||Low|
|Capacity Utilization||50% - 88%||50%||67% - 94%||50% - 88%|
|Typical Applications||Data archive, backup to disk, high availability solutions, servers with large capacity requirements||Fast databases, application servers||Large databases, file servers, application servers||Data archive, backup to disk, high availability solutions, servers with large capacity requirements|
|Types of RAID||Software-Based||Hardware-Based||External Hardware|
|Description||Best used for large
block applications such as data warehousing or video streaming. Also
where servers have the available CPU cycles to manage the I/O intensive
operations certain RAID levels require.
Included in the OS, such as Windows®, Netware, and Linux. All RAID functions are handled by the host CPU which can severely tax its ability to perform other computations.
|Best used for small
block applications such as transaction oriented databases and web
Processor-intensive RAID operations are off-loaded from the host CPU to enhance performance.
Battery-back write back cache can dramatically increase performance without adding risk of data loss.
|Connects to the server via a standard controller. RAID functions are performed on a microprocessor located on the external RAID controller independent of the host.|
Only requires a standard controller
|Data protection and
performance benefits of RAID
More robust fault-tolerant features and increased performance versus software-based RAID
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