HP ML150 HP ProLiant Intel-based 100-series G6 server technology - Page 11

I/O technologies ProLiant 100-series G6 servers incorporate PCI Express, Serial-Attached SCSI (SAS), and Serial ATA (SATA) I/O technologies. PCI Express lets administrators add expansion cards with various capabilities to the system. SAS is a serial communication protocol for direct-attached storage devices such as SAS and SATA hard drives. PCI Express technology All ProLiant G6 servers support the PCIe 2.0 specification. PCIe 2.0 has a per-lane signaling rate of 5 Gb/s which is double the per-lane signaling rate of PCIe 1.0 (Figure 4). Figure 4. PCIe data transfer rates Lane 1 Send Lane 1 Receive Source Lane n Send Lane n Receive Target Link size x1 x4 x8 x16 Max. bandwidth (Send or receive) PCIe 1.0 PCIe 2.0 250 MB/s 500 MB/s 1 GB/s 2 GB/s 2 GB/s 4 GB/s 4 GB/s 8 GB/s Total (Send and receive) PCIe 1.0 PCIe 2.0 500 MB/s 1 GB/s 2 GB/s 4 GB/s 4 GB/s 8 GB/s 8 GB/s 16 GB/s PCIe 2.0 is completely 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. Table 3 shows the level of interoperability between PCIe cards and PCIe slots. Table 3. PCIe device interoperability PCIe device type x4 Connector x4 Link x8 Connector x4 Link x4 card x4 operation x4 operation x8 card Not allowed x4 operation x16 card Not allowed Not allowed x8 Connector x8 Link x4 operation x8 operation Not allowed x16 Connector x8 Link x4 operation x8 operation x8 operation x16 Connector x16 Link x4 operation x8 operation x16 operation HP Smart Array and SAS/SATA technology The newest serial PCIe 2.0-capable Smart Array controllers use SAS technology, a point-to-point architecture in which each device connects directly to a SAS port rather than sharing a common bus as with parallel SCSI devices. 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 higher signaling rates.3 3 For more information about SAS technology, refer to the HP technology brief titled "Serial Attached SCSI storage technology" available at http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01613420/c01613420.pdf . 11