Users guide

Intel® RAID Software User Guide 26
2.4.9 UEFI 2.0 Support
UEFI 2.0 provides MegaRAID customers with expanded platform support. The
MegaRAID UEFI 2.0 driver, a boot service device driver, handles block IO requests and
SCSI pass-through (SPT) commands, and offers the ability to launch pre-boot MegaRAID
management applications through a driver configuration protocol (DCP). The UEFI driver
also supports driver diagnostic protocol, which allows administrators to access pre-boot
diagnostics.
2.4.10 Number of Physical Disks
Your configuration planning for the SAS RAID controller depends in part on the number
of physical disks that you want to use in a RAID array. The number of drives in an array
determines the RAID levels that can be supported. Only one RAID level can be assigned
to each virtual disk.
2.4.11 MegaRAID Fast Path
The MegaRAID Fast Path Premium Feature is a high performance IO Accelerator
technology for Solid State Drive RAID Arrays connected to a MegaRAID adapter. There
are two “Levels” to this feature. Level 1 Fast Path enabled by default without PFK. The
“Standard” or Level 1 Fast Path pertains to general IO Path improvements to Write
Through data transfers. Additionally, controller cache tuning has resulted in
improvements to configurations leveraging write back mode.
Level 2 Fast Path enabled automatically with Intel
®
RAID Premium Feature Key
AXXRPFKSSD or AXXRPFKSSD2 installed. Level 2 Fast Path is SSD-centric. This is
where the Premium Feature kicks in by supporting full optimization of SSD Virtual Disk
groups. With this premium feature enabled, Solid State Drive configurations tuned for
small, random block-size IO activity -- typical of transactional database applications --
can sustain higher numbers of IO READs Per Second, compared with Level 1 Fast Path.
The performance levels reached with this solution are equivalent to those of much costlier
Flash-based adapter card solutions.
Refer to Intel
®
RAID Premium Feature Key AXXRPFKSSD, AXXRPFKDE, and
AXXRPFKSNSH Installation Guide (E88588-00x) or Intel
®
RAID Premium Feature Keys
AXXRPFKSSD2, AXXRPFKDE2, and AXXRPFKSNSH2 Installation Guide (G29824-
00x) for description of the Premium Feature Key (PFK).
2.4.12 4K Sector Drive Support
The disk drive industry is in transition to support disk drives with native formatting of 4K
sectors. 4K formatted drives provide an opportunity to improve capacity and error
correction efficiencies as capacities grow, and as improvements in error correction are
implemented. Drives supporting 4K sectors will also support a 512 byte emulation mode
which will allow the drive to be operated with legacy OS and hardware products that do
not support 4K byte sectors. Intel
®
plans to implement 4K sector support on all new