Users Guide

● Number Of Virtual Disks Per Controller
● Calculation For Maximum Virtual Disk Size
You may also want to review the following sections:
● RAID Controller Read, Write, Cache, And Disk Cache Policy
● Understanding Hot spares
● Controller - Supported Stripe Sizes
● Time Delay In Displaying Configuration Changes
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.
Virtual disk considerations for controllers
In addition to the considerations described in this section, you should also be aware of the controller limitations described in
Number of Physical Disks per Virtual Disk for the following controllers:
Table 37. Virtual disk considerations for controllers
Virtual disk considerations for controllers
● PERC H310 Adapter
● PERC H310 Mini
Monolithic
● PERC H310 Mini Blades
● PERC H710 Adapter
● PERC H710 Mini
Monolithic
● PERC H710 Mini Blades
● PERC H710P Adapter
● PERC H710P Mini
Monolithic
● PERC H710P Mini
Blades
● PERC H810 Adapter
● PERC H330 Adapter
● PERC H330 Mini Monolithic
● PERC H330 Mini Blades
● PERC H330 Embedded
● PERC H730 Adapter
● PERC H730 Mini Monolithic
● PERC H730 Mini Blades
● PERC H730P Adapter
● PERC H730P Mini
Monolithic
●
PERC H730P Mini Blades
● PERC H730P Slim
● PERC H830 Adapter
● PERC H840 Adapter
● PERC H740P Adapter
● PERC H740P Mini Monolithic
● PERC FD33xD/FD33xS
● PERC H730P MX
● PERC H745P MX
● PERC H745P Front
● PERC H745 Front
● PERC H345 Front/Adapter
● PERC H755 Front/Adapter
● PERC H755N Front
● PERC H755 MX
● PERC S130
● PERC S140
● PERC S150
NOTE: The order of the controllers displayed on Storage Management may differ with the order of the controllers displayed
in the Human Interface (HII) and PERC Option ROM. The order of the controllers does not cause any limitation.
The following considerations apply when creating virtual disks:
● Creating virtual disks on controllers — When you create a virtual disk, you specify which physical disks are to be included
in the virtual disk. The virtual disk you create spans the specified physical disks. Depending on the size of the virtual disk,
the virtual disk may not consume all of the space on the physical disks. Any leftover space on the physical disks cannot be
used for a second virtual disk unless the physical disks are of equal size. In addition, when the physical disks are of equal size
and you use the leftover space for a second virtual disk, this new virtual disk cannot expand to include any physical disks not
included in the original virtual disk.
● Space allocation when deleting and creating virtual disks on controllers — When you delete a virtual disk, you free up or
make available space on the physical disks that was being used by the deleted virtual disk. If you have created several virtual
disks on a disk group, then deleting virtual disks can result in pockets of free space residing in various locations on the
physical disks. When you create a new virtual disk, the controller must decide which free space on the physical disks to
allocate to the new virtual disk. The PERC controllers look for the largest area of free space and allocate this space to the
new virtual disk.
● SCSI limitation of 2TB — Virtual disks created on a PERC controller cannot be created from physical disks with an aggregate
size greater than 2TB. This is a limitation of the controller implementation. For example, you cannot select more than 30
physical disks that are 73GB in size, regardless of the size of the resulting virtual disk. When attempting to select more than
30 disks of this size, a pop-up message is displayed indicating that the 2TB limit has been reached, and that you should
select a smaller number of physical disks. The 2TB limit is an industry-wide SCSI limitation.
● Expanding virtual disks — You can only use the Reconfigure task to expand a virtual disk that uses the full capacity of its
member physical disks.
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Virtual Disks