Dell EqualLogic PS6210XS EqualLogic Group Manager Administrator s Guide PS Ser - Page 384

Choosing a RAID Policy, Dell EqualLogic Group, Manager CLI Reference Guide

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Choosing a RAID Policy When selecting a RAID policy, you should consider the level of data protection you require, as well as I/O performance, capacity needs, and the types of drives contained in your PS Series array. Table 106. RAID Policies summarizes best practices for RAID policy selection. Table 106. RAID Policies RAID Policy RAID 10 RAID 6 RAID 6 Accelerated RAID 50 Recommended Usage Scenarios Recommended Drive Configuration Applications and workloads requiring the highest levels of I/O performance for random writes Systems containing 10K and 15 K RPM drives Applications requiring the highest levels of data protection and reliability. Situations in which I/O performance for random writes is not a key factor. Systems containing 7200 RPM SATA or Nearline SAS (NL-SAS) drives. Systems containing 24 or more drives. Optimizes the use of solid-state drives for critical data Supported only on arrays that contain both solid state (SSD) and hard disk (HDD) drives. For these systems, it is the only available RAID policy. It is not a user-selectable option. Applications requiring an optimal combination of performance, availability, and capacity Systems containing fewer than 24 drives. Systems containing 10K and 15K RPM drives. NOTE: You cannot select RAID 50 for PS6610 arrays from the GUI. Instead, you must use the CLI command member select raid-policy. See the Dell EqualLogic Group Manager CLI Reference Guide for more information. RAID 5 Dell recommends not using RAID 5 for any None. business-critical data. RAID 5 carries higher risks of encountering an uncorrectable drive error during a rebuild, and therefore does not offer optimal data protection. RAID 5 can only be configured using the CLI. For more information about RAID policies on PS Series systems, review the Dell Technical Report entitled PS Series Storage Arrays: Choosing a Member RAID Policy, which you can download from the following location: http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/19861480 Table 107. RAID Level Characteristic Comparison compares the performance of the supported RAID levels for different workload requirements. Table 107. RAID Level Characteristic Comparison Workload Requirement Capacity RAID 5 Excellent RAID 6 Good Data availability Poor Best Sequential reads Excellent Excellent Sequential writes Good Good RAID 10 Fair Excellent Excellent Good RAID 50 Good Fair Excellent Good 384 Reference: GUI Panels, Wizards, and Dialog Boxes

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Choosing a RAID Policy
When selecting a RAID policy, you should consider the level of data protection you require, as well as I/O performance, capacity
needs, and the types of drives contained in your PS Series array.
Table 106. RAID Policies
summarizes best practices for RAID policy
selection.
Table 106. RAID Policies
RAID Policy
Recommended Usage Scenarios
Recommended Drive
Configuration
RAID 10
Applications and workloads requiring the highest
levels of I/O performance for random writes
Systems containing 10K and 15 K RPM drives
RAID 6
Applications requiring the highest levels of data
protection and reliability. Situations in which I/O
performance for random writes is not a key factor.
Systems containing 7200 RPM SATA or Nearline
SAS (NL-SAS) drives. Systems containing 24 or
more drives.
RAID 6 Accelerated
Optimizes the use of solid-state drives for critical
data
Supported only on arrays that contain both solid
state (SSD) and hard disk (HDD) drives. For these
systems, it is the only available RAID policy. It is not
a user-selectable option.
RAID 50
Applications requiring an optimal combination of
performance, availability, and capacity
NOTE: You cannot select RAID 50 for
PS6610 arrays from the GUI. Instead, you
must use the CLI command member select
raid-policy. See the
Dell EqualLogic Group
Manager CLI Reference Guide
for more
information.
Systems containing fewer than 24 drives. Systems
containing 10K and 15K RPM drives.
RAID 5
Dell recommends not using RAID 5 for any
business-critical data. RAID 5 carries higher risks
of encountering an uncorrectable drive error during
a rebuild, and therefore does not
offer
optimal data
protection. RAID 5 can only be
configured
using
the CLI.
None.
For more information about RAID policies on PS Series systems, review the Dell Technical Report entitled
PS Series Storage Arrays:
Choosing a Member RAID Policy
, which you can download from the following location:
Table 107. RAID Level Characteristic Comparison
compares the performance of the supported RAID levels for
different
workload
requirements.
Table 107. RAID Level Characteristic Comparison
Workload Requirement
RAID 5
RAID 6
RAID 10
RAID 50
Capacity
Excellent
Good
Fair
Good
Data availability
Poor
Best
Excellent
Fair
Sequential reads
Excellent
Excellent
Excellent
Excellent
Sequential writes
Good
Good
Good
Good
384
Reference: GUI Panels, Wizards, and Dialog Boxes