Server Administrator Storage Management 8.3 User’s Guide

Number Of Physical Disks Per Virtual Disk

There are limitations on the number of physical disks that can be included in the virtual disk. These limitations depend on the controller. When creating a virtual disk, the controllers support some stripes and spans (methods for combining the storage on physical disks). Since, the number of total stripes and 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.