HP 381513-B21 HP Smart Array Controller technology, 3rd edition - Page 5

Figure 1. PCIe data transfer rates Lane 1 Send Lane 1 Receive Source Target Lane n Send Lane n Receive 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 NOTE: 10 bits of signaling are required to transport one Byte of data. Consequently in Figure 1, 5 Gb/s is shown as 500MB/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 2 shows the level of interoperability between PCIe cards and PCIe slots. Table 1. PCIe device interoperability PCIe device type x4 card x8 card x16 card x4 Connector x4 Link x4 operation Not allowed Not allowed x8 Connector x4 Link x4 operation x4 operation 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 SAS/SATA technology The newest serial, PCIe 2.0 capable Smart Array controllers use Serial Attached SCSI (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.1 The same Smart Array controllers are compatible with Serial Advanced Technology Attachment (SATA) technology and include the following features to enhance performance and maintain data availability and reliability: • SAS and SATA compatibility - The ability to use either SAS or SATA disk drives lets administrators deploy drive technology that fits each computing environment. HP Smart Array controllers can manage both SAS arrays and SATA arrays. Smart Array configuration utilities help administrators configure arrays correctly so that data remains available and reliable. 1 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 . 5