HP P3410A - NetRAID 1M RAID Controller Installation And Configuration Manual page 27

Chapter 2
With the HP NetRAID-2M adapter, you can span up to eight RAID 5
arrays, although the total number of disks in the RAID 50 logical drive
is limited by the number of disks that can be attached to the two SCSI
channels. For example, if two Rack Storage/12 enclosures are used, the
maximum number of disks in a RAID 50 logical drive is 24.
RAID 50 gives good performance if you have a high volume of small, random
transfers.
RAID 50 Disadvantages
Capacity expansion is an offline operation only.
Performance is slower than RAID 0 or RAID 10.
RAID 50 Summary
Choose RAID 50 if you need a large logical drive size, and cost, availability,
and performance are equally important. RAID 50 performs best for I/O-
intensive, high read/write ratio applications such as transaction processing.
Table 2-1. RAID Level Summary for RAID Levels 0 to 5
RAID Level
Also Known As
Fault Tolerance
Redundancy Type
Hot Spare Option
Disks Required
Usable Capacity
Capacity
Reduction
Read Performance
number of disks)
Random Write
Performance
Sequential Write
Performance
Typical Usage
writes with no need
for fault tolerance
RAID 0 RAID 1
striping mirroring
no yes
none duplicate
no yes
one or more two
greatest least
none 50%
fast (depends on intermediate
fastest intermediate
fastest intermediate
Rapid reads and Mostly small
random writes with
fault tolerance
RAID Overview
RAID 5
striping with
distributed parity
yes
parity
yes
three or more
intermediate
capacity of one disk
fast
slow
slowest
Mostly small,
random transfers
with fault tolerance
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