HP StorageWorks 4400, Installation Manual

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See Table 2 for a comparison of the different RAID levels.
Table 2 Raid Level Comparison
RAID meth-
od Data redund-
ancy Best practices Summary
striping none
IMPORTANT : HP does not recom-
mend using Vraid0 for virtual
disks when high availability is
required. Consider Vraid0 only
for noncritical storage. Vraid0
virtual disks provide the best per-
formance for applications that use
random I/O.
Vraid0 is optimized for I/O
speed and efficient use of
physical disk capacity, but
provides no data redund-
ancy.
Vraid0
striping and
mirroring
high
In general, Vraid1 virtual disks
provide better performance char-
acteristics over a wider range of
application workloads than
Vraid5.
Vraid1 is optimized for data
redundancy and I/O speed,
but uses the most physical
disk space.
IMPORTANT :
Vraid1 uses about 100%
more physical disk space
than Vraid0.
Vraid1
striping and
parity
medium
Vraid5 virtual disks provide as
good or better performance than
Vraid1 for applications that use
sequential writes. Vraid5 has
much lower random write perform-
ance in comparison to Vraid1,
but has much higher capacity ef-
ficiency.
Vraid5 provides a balance
of data redundancy, I/O
speed and efficient use of
physical disk space. Vraid5
uses about 20% more phys-
ical disk space than Vraid0.
Vraid5
striping and
double par-
ity
very high
Performance characteristics of
Vraid6 for random and sequential
write workloads will be slightly
slower than Vraid5. Vraid6
provides the highest level of re-
dundancy protection of all the
Vraid types. Vraid6 is similar to Vraid5,
but provides a higher level
of redundancy by storing
two parity blocks per stripe
instead of one. Vraid6 uses
33% more physical disk
space than Vraid0.
Vraid6
NOTE:
For best practice information, see the
HP StorageWorks 4400 Enterprise Virtual Array configuration
best practices white paper available at:
http://h18006.www1.hp.com/storage/arraywhitepapers.html?jumpid=reg_R1002_USEN
HP StorageWorks 4400 Enterprise Virtual Array installation guide 19