The Create Virtual Disk Advanced Wizard allows you to specify the read, write, and cache policy, and parameters
such as RAID level, bus protocol, media type, and encrypted disk for
the virtual disk. You can also select the physical disks and the controller
connector. You must have a good knowledge of RAID levels and hardware,
to use the Advanced Wizard. If you want the wizard to choose a recommended
virtual disk configuration for you, select the Express
Wizard option.
NOTE: This task is not supported
on PERC hardware controllers running in HBA mode.
To create a virtual disk using the Create Virtual Disk Advanced Wizard:
On the left-hand side of the Server
Administrator page, expand Storage.
Click on the <PERC Controller>.
Click on Virtual Disks.
The Virtual Disk(s) on Controller
<Controller Name> page is displayed.
Click Go to the Create Virtual
Disk Wizard.
The Create Virtual Disk Wizard
(Step 1) <Controller Name> page is displayed.
Select the Advanced Wizard option.
To make sure that only encrypted physical
disks are used to create the virtual disk, select Yes from the Create Encrypted Virtual Disk drop-down
list.
The RAID levels are available for selection based
on the number of encrypted physical disks.
If you select No, the RAID levels are available based on the total
number of physical disks present on the system.
Select the required RAID level from the drop-down
list.
Depending on the controller, Concatenated enables you to combine the storage capacity of several disks or
to create a virtual disk using a single physical disk. For more information
on the number of supported physical disks supported by Concatenated, see Number Of Physical
Disks Per Virtual Disk. Using Concatenated does not provide data redundancy or affect the read/write performance.
Select RAID 0 for striping.
This selection groups n disks together as a large virtual disk
with a total capacity of n disks. Data is alternately stored in the
disks so that they are evenly distributed. Data redundancy is not
available in this mode. Read/write performance is enhanced.
Select RAID 1 for mirroring
disks. This selection groups two disks as one virtual disk with the
capacity of a single disk. The data is replicated on both disks. When
a disk fails, the virtual disk continues to function. This feature
provides data redundancy and good read performance, but slightly slower
write performance. The system must have at least two physical disks
to use RAID 1.
Select RAID 5 for striping
with distributed parity. This selection groups n disks together
as one large virtual disk with a capacity of (n-1) disks. When a disk
fails, the virtual disk continues to function. This feature provides
better data redundancy and read performance, but slower write performance.
The system must have at least three physical disks to use RAID 5.
Select RAID 6 for striping
with additional distributed parity. This selection groups n disks as one large virtual disk with a capacity of (n- 2) disks.
The virtual disk remains functional with up to two disk failures.
RAID 6 provides better read performance, but slower write performance.
The system must have at least four physical disks to use RAID 6.
Select RAID 10 for striping
over mirror sets. This selection groups n disks together as
one large virtual disk with a capacity of (n/2) disks. Data is striped
across the replicated mirrored pair disks. When a disk fails, the
virtual disk continues to function. The data is read from the surviving
mirrored pair disk. This feature provides the best failure protection
and read/write performance. The system must have at least four physical
disks to use RAID 10. For PERC controllers with firmware version 6
and later, RAID 10 also allows you to create a single span virtual
disk with 22 or 26 physical drives.
Intelligent Mirroring — Automatically
calculates the span composition based on the physical disks you select.
Spans are not displayed on this page. Select Continue to view the span grouping on the Summary page.
Click Exit Wizard to cancel the virtual disk
creation.
Storage Management calculates the optimum
span composition as follows:
Determining span calculation:
Calculating the number of disks that can be utilized
from the selected disks.
Maximizing the number of spans to increase the I/O
performance
Determining the mirror for the physical disks: The
mirror is determined in a way that ensures maximum redundancy. The
algorithm also tries to match a physical disk for its mirror, to
a disk that is almost the same size. However, Intelligent
Mirroring gives priority to size over redundancy.
The algorithm determines the candidate mirror in the following
order:
Across connectors at the same level of enclosure
and same size.
Across connectors in the enclosure that are not at
the same level but of same size.
Across enclosures connected to the same connector
and to a disk of the same size.
Within the enclosure with a physical disk of acceptable
size difference.
Across connectors at the same level of enclosure
and of acceptable size difference.
Across connectors in the enclosure that are not at
the same level of the enclosure but with a physical disk of acceptable
size difference.
If the size difference is not acceptable, the disk is not
mirrored and hence dropped from the span. The number of spans and
disks in the span is recalculated.
NOTE: It is recommended that
you use Intelligent Mirroring to create RAID
10 across enclosures for simple and optimum configuration.
NOTE: To view the
redundancy across enclosures achieved through Intelligent
Mirroring, click the virtual disk and view the physical
disk IDs in each span, which are from alternate enclosures.
Select RAID 50 to implement
striping across more than one span of physical disks. RAID 50 groups n*s disks as one large virtual disk with a capacity of s*(n-1) disks, where s is the number of spans and n is the number of disks
within each span.
Select RAID 60 to implement
striping across more than one RAID 6 span. RAID 60 groups n*s disks as one large virtual disk with a capacity of s*(n-2) disks, where s is the number of spans and n is the number
of disks within each span. RAID 60 provides increased data protection
and better read performance, but slower write performance.'