The integrated RAID solution provides cost benefits for the server or workstation market where
the extra performance, storage capacity, and/or redundancy of a RAID configuration are
required. The two components of integrated RAID are:
Integrated Mirroring (IM) provides features of RAID 1
Integrated Striping (IS) provides features of RAID 0
By simplifying the IM and IS configuration options and by providing firmware support in its host
adapters, integrated RAID can offer the integrated RAID solution at a lower cost than a full-blown RAID implementation.
This document provides a reference to expedite the configuration of integrated RAID.
Notes:
- Integrated RAID offers advanced features including I/O performance with additional data
security; however, there are several considerations of which to be aware.
- Only one RAID configuration (logical drive) is allowed.
- Integrated RAID may take an extended period of time to complete the initialization after
the RAID setup. The amount of time required depends whether the initialization is
completed within the BIOS-based utility or completed with the operating system-based
utility. The amount of time required also depends on the complexity of the configuration
and capability of the system being configured.
- Unlike a hardware controller, integrated RAID consumes system resources such as CPU
cycles and system memory to handle I/O requests; in a situation where the CPU is
heavily loaded, the I/O performance may drop significantly.
2. Integrated RAID Implementation Guidelines
2.1 Integrated Mirroring
Integrated Mirroring (IM) provides data protection for the system volume. The purpose is to
safeguard critical information, such as the operating system.
IM can be set up with two hard disk drives to maintain high performance, as well as data
availability and fault tolerance. If one disk drive fails, the hot swap drive mechanism allows the
system to maintain operation while the failed disk drive can be replaced. In addition, the hot
spare capability enables the system to automatically replace the defective drive with a standby
disk.
IM requires extra time synchronization in BIOS mode as compared to the synchronization time
in operating system mode. In BIOS mode (<Ctrl>+<C>), 1 hour for each 5 gigabytes of hard
drive capacity is typically required to complete initializing the mirror. For example, for two 100
gigabyte drives configured in a RAID 1 mirroring, 18-20 hours should be allowed for the
initialization to complete.
The IM firmware uses queue tagged I/Os to allow SCSI I/Os to continue on the IM volume while
the volume is re-synchronized in the background. The host driver may optionally suspend the
resynchronization operation while performing domain validation or while configuring Ultra320
SCSI expanders.
2.2 Integrated Striping
Integrated Striping (IS) is available for applications that require faster I/O performance and
higher storage capacity for non critical data. With this option there is no drive failover. Failure of
a drive results in a loss of all data on the drives holding the data stripe. By reading and writing
data concurrently across several disks, IS offers excellent performance as compared to a single
physical disk. However, the risk of data loss increases because a single disk failure will cause
the loss of the entire logical drive.
The IS configuration is available only for new installations. Migration of data with existing disks
integrated RAID Configuration Guide.pdf
