Glossary

spans is limited, the number of physical disks that can be used is also limited. The limitations on stripes
and spans affect the possibilities for concatenation and RAID levels as follows:
• Maximum number of spans affects RAID 10, RAID 50, and RAID 60.
• Maximum number of stripes affects RAID 0, RAID 5, RAID 50, RAID 6, and RAID 60.
• Number of physical disks in a mirror is always 2. This property affects RAID 1 and RAID 10.
If RAID 50 and RAID 60, you can use a greater number of physical disks than is possible for other RAID
levels. RAID 10 on a SAS controller with firmware version 6.1 can use a maximum of 256 physical disks.
However, the number of connectors on the controller imposes limitations on how many physical disks
can be included in a virtual disk when using RAID 10, RAID 50, or RAID 60. This is because only a limited
number of physical disks can be physically attached to the controller.
For information about the maximum number of physical disks supported by a virtual disk, see the virtual
disk specifications for the controller in Supported Features.
Related Links
Virtual Disk Considerations For PERC S100, S110, S130, And S300 Controllers
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, SATA, And ATA RAID Controllers
When using a SCSI, SATA, and 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.
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