Disk Drive Sizes And Types - HPE D3600 User Manual

The following table compares the different RAID levels.
Summary
RAID0 RAID0 is optimized for I/O
speed and efficient use of
physical disk capacity, but
provides no data redundancy. storage. RAID0 LUNs provide the
RAID1 RAID1 is optimized for data
redundancy and I/O speed,
but uses the most physical
disk space. IMPORTANT:
RAID1 uses about 100% more
physical disk space than
RAID0 and 70% more than
RAID5.
RAID5 RAID5 protects against failure
of one drive (and failure of
particular multiple drives).
RAID 50 is a nested RAID
method that uses RAID 0
striping across RAID 5 arrays.
RAID6 RAID6+0 allows
administrators to split the
RAID 6 storage across
multiple external boxes. RAID
60 requires a minimum of
eight drives. RAID 60 is a
nested RAID method that uses
RAID 0 block-level striping
across multiple RAID 6 arrays
with dual distributed parity.
With the inclusion of dual
parity, RAID 60 will tolerate
the failure of two disks in each
spanned array without loss of
data.
RAID6 Allocates the equivalent of two
with parity drives across multiple
Advance drives and allows
Data simultaneous write operations
Guarding Distributed Data Guarding
(ADG) (RAID 5): Allocates parity data
across multiple drives and
allows simultaneous write
operations. Drive Mirroring
(RAID 1 and 1+0 Striped
Mirroring): Allocates half of the
drive array to data and the
other half to mirrored data,
providing two copies of every
file

Disk drive sizes and types

RAID arrays should be composed of disk drives of the same size and performance capability.
When drives are mixed within a disk enclosure, the usable capacity and the processing ability
of the entire storage sub-system is affected. For example, when a RAID array is composed of
different sized drives, the RAID array defaults to the smallest individual drive size, and capacity
in the larger drives goes unused.
Best practices
IMPORTANT: Do not use RAID0 for
LUNs if fault tolerance is required.
Consider RAID0 only for noncritical
best performance for applications
that use random I/O.
In general, RAID1 virtual disks
provide better performance
characteristics over a wider range
of application workloads than
RAID5.
RAID 50 tolerates one drive failure
in each spanned array without loss
of data. RAID 50 requires less
rebuild time than single RAID 5
arrays RAID 50 requires a minimum
of six drives.
RAID6 is most useful when data loss
is unacceptable but cost is also an
important factor. The probability that
data loss will occur when an array
is configured with RAID6 is less than
it would be if it was configured with
RAID5. However, write performance
is lower than RAID5 because of the
two sets of parity data.
Organizations implementing a large
drive array should consider RAID 6
because it can tolerate up to two
simultaneous drive failures without
downtime or data loss.
Data redundancy RAID method
None Striping
High Mirroring
Medium Striping and
parity
High Striping and
parity
High Striping and
parity
Preliminary tasks 25