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Virtual Disks
Dell™OpenManage™ServerAdministratorStorageManagementUser'sGuide
In order to implement RAID functions, RAID controllers 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. Depending on the RAID
level used, the virtual disk may retain redundant data in case of a disk failure or have particular performance attributes. See "Understanding RAID Concepts"
for more information.
Considerations Before Creating Virtual Disks
Different controllers have particular characteristics in the way they implement virtual disks. These characteristics may include use of disk space, limitations on
the number of virtual disks per controller, and so on. It can be helpful to understand these characteristics before creating virtual disks on the controller.
The following sections describe controller information that applies to virtual disks:
l "Virtual Disk Considerations for PERC 3/SC, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si, 4e/Di, CERC ATA100/4ch, PERC 5/E, PERC 5/i, PERC 6/E, and
PERC 6/I Controllers"
l "Virtual Disk Considerations for PERC 3/Si, 3/Di, CERC SATA1.5/6ch, and CERC SATA1.5/2s controllers"
l "Problems Associated With Using the Same Physical Disks for Both Redundant and Nonredundant Virtual Disks"
l "Virtual Disk Considerations on Linux"
l "Number of Physical Disks per Virtual Disk"
l "Maximum Number of Virtual Disks per Controller"
l "Calculation for Maximum Virtual Disk Size and the Create Virtual Disk Express Wizard"
You may also want to review the following sections:
l "RAID Controller Read, Write, Cache, and Disk Cache Policy"
l "Understanding Hot Spares"
l "Controller-supported Stripe Sizes"
l "Rescan to Update Storage Configuration Changes"
l "Time Delay in Displaying Configuration Changes"
Virtual Disk Considerations for PERC 3/SC, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si,
4e/Di, CERC ATA100/4ch, PERC 5/E, PERC 5/i, PERC 6/E, and PERC 6/I Controllers
Considerations Before Creating Virtual Disks
Creating Virtual Disks
Reconfiguring/Migrating Virtual Disks
Starting and Target RAID Levels for Virtual Disk Reconfiguration
Maintain Integrity of Redundant Virtual Disks
Rebuilding Redundant Information
Virtual Disk Properties and Tasks
Create Virtual Disk Express Wizard (Step 1 of 2)
Create Virtual Disk Express Wizard (Step 2 of 2)
Create Virtual Disk Advanced Wizard (Step 1 of 4)
Create Virtual Disk Advanced Wizard (Step 2 of 4)
Create Virtual Disk Advanced Wizard (Step 3 of 4)
Create Virtual Disk Advanced Wizard (Step 4 of 4)
Span Edit
Virtual Disk Task: Reconfigure (Step 1 of 3)
Virtual Disk Task: Reconfigure (Step 2 of 3)
Virtual Disk Task: Reconfigure (Step 3 of 3)
Format and Initialize; Slow and Fast Initialize
Virtual Disk Task: Delete
Virtual Disk Task: Rename
Virtual Disk Task: Change Policy
Split Mirror
Unmirror
Assign and Unassign Dedicated Hot Spare
Virtual Disk Task: Replace Member Disk (Step 1 of 2)
Virtual Disk Task: Replace Member Disk (Step 2 of 2)
NOTE: Virtual disks can only be created on a RAID controller.
NOTE: In addition to this document, review the hardware documentation that is provided with the controllers. Reviewing the hardware documentation
along with this document may provide a better understanding of the controller limitations.