User's Manual

SAS RAID Controllers
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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.
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Channel Redundant Virtual Disks
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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. See the following for more information:
l "Thermal Shutdown for Enclosures"
l "Channel Redundancy and Thermal Shutdown"
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Creating Virtual Disks
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Does my controller support this feature? See "Supported Features."
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In order to implement RAID functions, you need to 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. See "What Is RAID?" for more
information.
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Before creating a virtual disk, you should be familiar with the information in "Considerations Before Creating Virtual Disks."
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Storage Management provides wizards to help you create a virtual disk:
l The Create Virtual Disk Express Wizard calculates an appropriate virtual disk layout based on the available space and controller considerations. Using
the Express Wizard, you can quickly create a virtual disk using recommended selections. See "Create Virtual Disk Express Wizard (Step 1 of 2)" for more
information.
l The Create Virtual Disk Advanced Wizard allows you to specify the read, write, and cache policy for the virtual disk. You can also select the physical
disks and the controller connector to be used. You need a good knowledge of RAID levels and hardware to use the Advanced Wizard. See "Create
Virtual Disk Advanced Wizard (Step 1 of 4)" for more information.
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You may also want to refer to the following related sections:
l "What Is RAID?"
l "Channel Redundancy and Thermal Shutdown" for information on creating a channel-redundant virtual disk
l "Virtual Disk Task: Delete"
l "Reconfiguring/Migrating Virtual Disks"
l "Physical Disk Properties and Tasks"
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Reconfiguring/Migrating Virtual Disks
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Does my controller support this feature? See "Supported Features."
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You can reconfigure or migrate a virtual disk in order to increase the disks capacity or change its RAID level.
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To reconfigure a virtual disk:
NOTE: Channel redundancy applies only to controllers that have both channels attached to a single external disk enclosure.