Specifications

I/O technologies

HP Integrity server blades support PCI Express (PCIe), SAS, multifunction 1GbE or 10GbE, and 8 Gb Fibre Channel. Future

releases are expected to provide supports for more I/O cards and protocols.

PCIe technology

The PCIe serial interface provides point-to-point connections between the chipset I/O controller hub and I/O devices.

Each PCIe serial link consists of one or more dual-simplex lanes. Each lane contains a send pair and a receive pair to

transmit data at the signaling rate in both directions simultaneously (figure 7). PCIe 1.0 has a signaling rate of 2.5 Gb/s

per direction per lane. PCIe 2.0 doubles the per-lane signaling rate of PCIe 1.0 from 2.5 Gb/s to 5 Gb/s. This flexibility

allows slower devices to transmit on a single lane with a relatively small number of pins while faster devices can

transmit on more lanes as required.

PCIe 2.0 is backward compatible with PCIe 1.0. A PCIe 2.0 device can be used in a PCIe 1.0 slot and a PCIe 1.0 device can

be used in a PCIe 2.0 slot. For best performance, however, each card should be used in a slot that supports its logical

link size.

Figure 7. PCIe bandwidth

HP Smart Array controllers

HP Integrity server blades support internal hard drives through integrated or optional HP Smart Array controllers. The

embedded HP Smart Array P410i Controller supports SAS SFF drives.

An optional battery-backed write cached (BBWC) Smart Array controller is available to interface with the HP MDS600 disk

array. A BBWC is also available as an option for the Smart Array controllers. The battery prevents information in the

buffer from being lost in case of an unexpected system shutdown. In the case of a complete system failure, IT

administrators can move the controller and disks to a different server where the controller flushes out the cache to the

disks after power is restored. In the case of a controller failure, administrators can move the cache module and disks to a

working controller where the cache is flushed out to the disks. The battery lasts up to two days without receiving any

power from the computer.

SAS technology

SAS is a serial communication protocol for direct-attached storage devices such as SAS and SATA Small Form Factor

(SFF) disk drives. It is a point-to-point architecture in which each device connects directly to a SAS port rather than

sharing a common bus, as parallel SCSI devices do. Point-to-point links increase data throughput and improve the ability

to locate and fix disk failures. More importantly, SAS architecture solves the parallel SCSI problems of clock skew and

signal degradation at high signaling rates.