User's Manual

216 Virtual Disks
The support provided by your operating system depends on the version of the
operating system and any updates or modifications that you have
implemented. In addition, you should investigate the capacity of your
peripheral devices to support a virtual disk that is larger than 1TB. For more
information, see your operating system and device documentation.
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, controllers support a certain number of stripes and spans
(methods for combining the storage on physical disks). Because 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 concatenation, 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 affects RAID 1 and
RAID 10.
In the case of RAID 50 and RAID 60, you can use a greater number of
physical disks than is possible for the 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 on how many physical disks a controller supports per virtual
disk, see the virtual disk specifications for the controller in Supported
Features.
Maximum Number of Virtual Disks per Controller
Controllers have limitations on how many virtual disks can be created on the
controller. For information on how many virtual disks the controller supports,
see the virtual disk specifications for the controller in Supported Features.