Technology implementation in HP ProLiant G7 servers

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Low-voltage DDR3 DIMMs
Our ProLiant G7 servers support low voltage (LV) DDR3 DIMMs. These DIMMS can operate at 1.35 V
instead of the standard 1.5 V. Since they require less power, they also require less cooling. Single-
rank and dual-rank LV DDR3 DIMMs run at 1066 MT/s using 1 or 2 DIMMs per channel (DPC), or
they run at 800 MT/s using 3 DPC.
The BIOS determines the DIMM population from the server and determines the operating voltage and
data rate capability from the DIMMs. The BIOS then sets the data rate based on that information.
ProLiant Memory Configuration Tool
DDR3 DIMMs from third-party memory resellers can vary greatly in quality and reliability. This is why
you should use only HP memory option kits to replace or add memory in ProLiant servers. HP uses
proprietary diagnostic tools and specialized server memory diagnostic tests that exceed industry
standards. This ensures the highest level of performance and availability for ProLiant servers. HP
memory option kits precisely match the capabilities and requirements of each ProLiant server and
prevent improper mixing of single-, dual-, and quad-rank DIMMs.
We simplify memory selection with the on-line ProLiant DDR3 Memory Configuration Tool
(www.hp.com/go/ddr3memory-configurator). It takes you through the steps to configure server
memory, and it provides an orderable parts list.
HP Smart Array technologies
HP Smart Array Serial Attached SCSI (SAS)-2 controllers deliver peak data bandwidth up to
600MB/s per physical link in each direction, or 1200MB/s when running in full duplex mode. These
controllers are fully compatible with 1.5-Gb/s and 3.0-Gb/s Serial ATA (SATA) technology.
The Smart Array controllers include configuration, management, and diagnostic tools for direct-attach
storage (DAS) and storage area network (SAN) configurations. HP Smart Array controllers can
connect to SAS expander devices. These devices expand the number of disk drives connected to a
Smart Array controller.
Smart Array controller options include the battery-backed write cache, flash-backed write cache, and
the HP Smart Array Advanced Pack. For a compatibility matrix and a list of the most up-to-date HP
Smart Array controllers, go to www.hp.com/products/smartarray.
Battery-backed write cache
The battery-backed write cache (BBWC) protects against data loss for up to two days. This is an
improvement for G7.
Flash-backed write-cache
The flash-backed write-cache (FBWC) system protects against data loss beyond the 48-hour battery
life limit of BBWC. FBWC has a larger cache size (up to 1GB) than BBWC (up to 512MB), but it
offers no performance advantage. During a power loss, the FBWC uses power from the super-
capacitors (Super-caps) to write DRAM cache data to NAND flash memory. NAND flash memory
does not need power to store cache data, so it preserves the data indefinitely. On the next server
power up, the FBWC restores the data to the DRAM modules. After the Smart Array controller verifies
that the data is correct, it transfers the data to the disk drives.