Software Support

Number Of Virtual Disks Per Controller
There are limitations on the number of virtual disks that can be created on the controller. For information about the
maximum number of virtual disks supported by a controller, see the virtual disk specifications for the controller in
Supported Features.
Calculation For Maximum Virtual Disk Size
The Create Virtual Disk Express Wizard displays the minimum and maximum values for the virtual disk size. This section
describes how the maximum possible size for the virtual disk is calculated based on the controller type. To identify the
controller type, see RAID Controller Technology: SCSI, SATA, ATA, and SAS.
SCSI, CERC SATA, And CERC ATA RAID Controllers
When using a SCSI, CERC SATA, or CERC ATA RAID controller, the controller calculates the maximum virtual disk size
based on your RAID level selection and the available physical disk space provided by all suitable physical disks attached
to the controller. For example, if the controller contains 12 physical disks with available space and you have specified a
RAID 5, then the controller calculates the maximum virtual disk size based on the disk space provided by the 12 physical
disks, because the 12 physical disks can be included in a RAID 5.
SAS RAID Controllers
When using a SAS controller, the controller calculates the maximum virtual disk size based on the available disk space
provided by the minimum number of physical disks required to create the RAID level you selected. For example, if you
specified a RAID 5, then the controller calculates the maximum virtual disk size based on three physical disks, because
only three physical disks are required to create a RAID 5.
Channel-Redundant Virtual Disks
When creating a virtual disk, it is possible to use disks attached to different channels to implement channel redundancy.
This configuration might be used for disks that reside in enclosures subject to thermal shutdown.
NOTE: Channel redundancy only applies to controllers that have more than one channel and that attach to an
external disk enclosure.
Related Links
SMART Thermal Shutdown
Channel Redundancy And Thermal Shutdown
Creating A Channel-Redundant Virtual Disk
Creating Virtual Disks
Does my controller support this feature? See Supported Features.
In order to implement RAID functions, you must create a virtual disk. A virtual disk refers to storage created by a RAID
controller from one or more physical disks. Although a virtual disk may be created from several physical disks, it is seen
by the operating system as a single disk.
Before creating a virtual disk, you should be familiar with the information in Considerations Before Creating Virtual
Disks.
Storage Management provides wizards to help you create a virtual disk:
• The Create Virtual Disk Express Wizard calculates an appropriate virtual disk layout based on the available
space and controller considerations. Using this wizard, you can quickly create a virtual disk using recommended
selections.
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