Choosing A Raid Level; Summary - HP 381513-B21 - Smart Array P800 Controller RAID Technology Brief

Choosing a RAID level

To choose the optimum RAID level for data protection in large arrays, IT managers should consider a
variety of factors, including:
• Fault tolerance (based on availability requirements)
• Cost effectiveness (based on storage efficiency or cost per gigabyte of usable capacity)
• Performance
The decision chart in Table 3 is an aid for determining which RAID level will provide the best solution
for a specific computing environment. For example, if cost effectiveness is of primary importance and
fault tolerance is of secondary importance, or vice versa, the best choice is RAID 6.
Table 3: Decision chart for choosing the optimum RAID level for large arrays
Most important
Cost effectiveness
Fault tolerance
Performance

Summary

RAID 6 with HP's patented Advanced Data Guarding technology provides an advanced level of data
protection for computing environments requiring a higher level of fault tolerance than RAID 5 and a
lower implementation cost than RAID 1. RAID 6 is best implemented when IT organizations need to
protect enterprise data at a lower cost than RAID 1 arrays and when performance is not an overriding
factor.
RAID 6 can effectively protect an array of up to the maximum number of drives supported by a variety
of Smart Array Controllers. A RAID 6 array can tolerate up to two simultaneous drive failures without
downtime or data loss. RAID 6 supports Online Spare Drives and Online RAID Level Migration from
any RAID level.
Secondary importance
Fault tolerance
→
Performance →
Cost effectiveness →
Performance
→
Cost Effectiveness →
Fault tolerance
→
RAID level choice
RAID 6 (ADG)
RAID 5
(RAID 0 if fault tolerance is not
needed)
RAID 6 (ADG)
RAID 1+0
RAID 5
(RAID 0 if fault tolerance is not
needed)
RAID 1+0
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