HP ProLiant Intel-based 100-series G6 servers

SAS-2

SAS-2 and PCIe 2.0 are among the technologies responsible for a significant increase in performance

over past generations of Smart Array controllers. The second-generation SAS (SAS-2) link speed

6 Gb/s is double the SAS-1 transfer rate. Operation at SAS-2 link speeds requires SAS-2 compliant

hard drives. SAS-2 eliminates the distinction between fanout and edge expanders by replacing them

with self-configuring expanders. SAS-2 enables zoning for enhanced resource deployment, flexibility,

security, and data traffic management. SAS-2 is also backward compatible with SAS-1.

Beginning with HP product releases in the first quarter of 2009, Smart Array controllers are SAS-2

capable. In fully supported controllers, 6-Gb/s SAS technology allows Smart Array controllers to

deliver peak data bandwidth up to 600 MB/s per physical link in each direction. SAS devices are

capable of sending and receiving data simultaneously across each physical link (full duplex mode).

When running full duplex, 6-Gb/s SAS technology can deliver peak data bandwidth up to 1200

MB/s.

The SAS-2 specification is compatible with both Serial SCSI and Serial ATA protocols for

communicating commands to SAS and SATA devices. SAS-2 compliant controllers are fully

compatible with 1.5-Gb/s and 3.0-Gb/s SATA technology.

For an up-to-date listing of HP Smart Array controllers that support the SAS-2 specification, see the

Smart Array controller matrix: www.hp.com/products/smartarray

HP Smart Array controllers based on PCIe 2.0

he Smart Array PCIe 2.0-based controllers are modular solutions with a common form factor,

hardware, and firmware. Any of the ProLiant 100-series G6 servers can use PCIe 2.0-based

controllers. All ProLiant 100-series G6 servers incorporate embedded SATA storage controllers, and

the Smart Array B110i software RAID is available. The Smart Array 410 incorporates Zero Memory

RAID (ZMR) and is available as an entry level hardware-based RAID. Administrators can choose the

cache size and can choose to include either the battery backed write cache (BBWC), or the Flash-

backed write cache (FBWC). With these options, ZMR can be upgraded to 512 BBWC and up to 1

GB with the FBWC.

Battery backed write cache

he BBWC system continues to be an option for capacity expansion (adding one or more physical

disks to an existing array). The Smart Array controller recalculates parity and balances the data

across all the disks. During the expansion, the BBWC preserves data and logical structures on the

array. The HP 650 mAh P-Series battery extends battery life up to 48 hours before recharging

becomes necessary.

NOTE:

The Smart Array P212 does not support 512 MB BBWC, and is only upgradeable to

256 MB BBWC

Flash-backed write cache

HP introduced the flash-backed write-cache (FBWC) system in the fourth quarter of 2009. The FBWC

uses NAND

flash devices to retain cache data and super-capacitors (Super-caps) instead of batteries

to provide power during a power loss. The FBWC offers significant advantages over the HP Battery-

backed write-cache (BBWC) system. Since the FBWC writes the contents of memory to flash devices,

Serial Attached SCSI-2 (SAS-2) is an American National Standards Institute (ANSI) standard from the INCITS T10 Technical

Committee on SCSI Storage Interfaces. SAS-2 is the successor to SAS-1.1 and SAS-1.

Non-volatile semiconductor memory that can be electronically erased and reprogrammed. No power is needed to maintain

data stored in the chip