Avago Technologies SAS 9300-4i Host Bus Adapter - Manual (Page 9)

LSI Corporation
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SAS-3 Integrated RAID Solution User Guide
November 2012 Chapter 2: Overview of Integrated RAID Mirrored Volumes
Operation of Mirrored Volumes
 Support for both SAS disks and SATA disks, although you cannot combine the two types of disks in the same
volume. However, an LSI SAS-3 controller can support one volume with SATA disks and a second volume with
SAS disks.
 Automatic background initialization after a volume is created.
 Consistency checking.
 Fusion-MPT architecture.
 Menu-driven, BIOS-based configuration utility.
 Error notification, in which the drivers update an OS-specific event log.
 Support for SCSI Enclosure Services (SES) status LED.
 Write journaling, which permits automatic synchronization of potentially inconsistent data after unexpected
powerdown situations.
 Use of metadata to store volume configuration on disks in a mirrored volume.
 Automatic background resynchronization while host I/O transactions continue.
 Background media verification, which makes sure that data on mirrored volumes is always accessible.
2.3 Operation of Mirrored Volumes
The LSI Integrated RAID solution supports one or two mirrored volumes on each LSI SAS-3 controller (or one mirrored
volume and one Integrated Striping volume). Typically, one of these volumes is the boot volume. Boot support is
available through the firmware of the LSI SAS-3 controller that supports the standard Fusion-MPT interface. The
run-time mirroring of the boot disk is transparent to the BIOS, the drivers, and the operating system. Host-based
status software monitors the state of the mirrored disks and reports any error conditions. The following figure shows
an Integrated Mirroring volume in which the second disk is a mirrored copy of the data on the first (primary) disk.
Figure 1 Typical Integrated Mirroring Implementation
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