Users Guide
Let us consider that the controller has three enclosures with six physical disks each (total number of available disks = 3 x 6 =18 disks). If you select four
disks per span, the controller will create four spans (18 disks/4 disks per span = 4 spans). The last two disks of the last enclosure will not be part of
RAID 10.
l Intelligent Mirroring — Automatically calculates the span composition based on the physical disks you select
Spans are not displayed on this page. Select Continue to view the span grouping in the Summary page ("Create Virtual Disk Advanced Wizard (Step 4 of
4).")
Storage Management uses the following intelligence to calculate the optimum span composition:
l Determining span calculation:
l Calculating the number of disks that can be utilized out of selected disks.
l Maximizing the number of spans in order to increase the I/O performance
l Determining the mirror for the physical disks:
The mirror is determined in a way that ensures maximum redundancy. The algorithm will also try to match a physical disk for its mirror to a disk
that is closest to it in size. However, Intelligent Mirroring places more importance on redundancy over size.
The algorithm determines the candidate mirror in the following order:
l Across connectors at the same level of enclosure and of same size
l Across connectors in the enclosure that are not at the same level but of same size
l Across enclosures connected to same connector and to a disk of same size
l Across connectors at the same level of enclosure and of acceptable size difference
l Across connectors in the enclosure that are not at the same level of the enclosure but with a physical disk of acceptable size difference
l Within the enclosure with a physical disk of acceptable size difference
If the physical disk cannot be mirrored because the size difference is not acceptable, the disk will not be mirrored and hence dropped from the
span, and number of span and disk in the span will be recalculated.
Click Continue when you have completed the disk selection. If you want to cancel the virtual disk, click Exit Wizard. If you want to return to the previous
screen and change your selections, click Go Back To Previous Page.
Create Virtual Disk Advanced Wizard (Step 3 of 4)
Does my controller support this feature? See "Supported Features."
This screen enables you to select attributes for the virtual disk. These attributes include the name, size and read, write, and cache policy. Depending on the
controller and your previous virtual disk selections, the items displayed on this screen can vary.
Do the following:
1. Type the name of the virtual disk in the Name text box.
The virtual disk name can contain only alphanumeric characters as well as spaces, dashes and underscores. The maximum name length depends on the
controller. In most cases, the maximum length is 15 characters. The name cannot start with a space or end with a space.
NOTE: On a SAS controller with firmware version 6.1 and later, RAID 10 supports only even number of disks per span and a maximum of 8 spans
with 32 disks.
NOTE: Selecting this option disables the Number of disks per span option.