User's Manual

224 Virtual Disks
protection and read/write performance. Your system must have at least
four disks to use RAID 10. For PERC controllers with firmware version
6 and later, RAID 10 also allows to create a single span virtual disk with
22 or 26 physical drives.
–
Intelligent Mirroring —Automatically calculates the span
composition based on the physical disks you select.
Spans are not displayed on this screen. Select
Continue to view the
span grouping on the
Summary screen. Click Exit Wizard to cancel
the virtual disk creation.
Storage Management calculates the optimum span composition as
follows:
• Determining span calculation:
- Calculating the number of disks that can be utilized from the
selected disks.
- Maximizing the number of spans to increase the I/O
performance
• Determining the mirror for the physical disks:
The mirror is determined in a way that ensures maximum possible
redundancy. The algorithm also tries to match a physical disk for its
mirror, to a disk that is almost the same size. However,
Intelligent
Mirroring
gives priority to size over redundancy.
The algorithm determines the candidate mirror in the following order:
• Across connectors at the same level of enclosure and of same size
• Across connectors in the enclosure that are not at the same level
but of same size
• Across enclosures connected to same connector and to a disk of
same size
• Within the enclosure with a physical disk of acceptable size
difference
• Across connectors at the same level of enclosure and of acceptable
size difference