User`s guide

10 Integrated Mirroring Overview
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• Provides automatic background resynchronization while host I/Os continue
• Supports media verification
Description
The IM feature provides mirroring for the boot volume, as shown in Figure 2-1. This is
accomplished through the firmware of a PERC 4/IM controller that supports the standard Fusion-
MPT interface. The runtime mirroring of the boot disk is transparent to the BIOS, drivers, and
operating system. Host-based status software monitors the state of the mirrored disks and reports
any error conditions. In Figure 2-1, the system is configured with a second disk as a mirror of the
first (primary) disk.
Figure 2-1. Typical Mainboard Implementation
Figure 2-2 shows the logical view and physical view of the mirroring configuration when there are
two disks in the mirrored volume.
Two Disk Drives
OS Mirrored
OS
NVSRAM
EEPROM
(For Configuration)
(For Write Journaling)
Internal
Memory
Bus
SCSI
PERC 4/IM
Controller