HP B- Accelerators Linux manual Enabling PCIe power override, Fio-update-iodrive

•fio-update-iodrive

For more information, see "Utilities reference (on page 40)."

Enabling PCIe power override

For PCIe IO Accelerators, if you have installed any dual IO Accelerator devices, such as the HP ioDrive2 Duo, then the device might require additional power than the minimum 25 W provided by PCIe Gen2 slots to properly function. Even if additional power is not required for your device, all dual IO Accelerator devices that receive additional power might benefit with improved performance.

HP ioDrive2 Duo devices must have additional power to properly function. For more information on which devices require additional power, see the HP PCIe IO Accelerator for ProLiant Servers Installation Guide.

Additional power can be provided in two ways:

•External power cable—This cable ships with all dual ioMemory devices. For information on installing this cable, see the HP PCIe IO Accelerator for ProLiant Servers Installation Guide.

NOTE: When a power cable is used, all of the power is drawn from the cable and no power is drawn from the PCIe slot.

•Enabling full slot power draw—Some PCIe slots provide additional power (often up to 75 W of power). If your PCIe slot is rated to provide at least 55 W, then you can allow the device to draw full power from the PCIe slot by setting a VSL module parameter. For more information on enabling this override parameter, see "Enabling the override parameter (on page 37)."

CAUTION: If the PCIe slot is not capable of providing the needed amount of power, then enabling full power draw from the PCIe slot might result in malfunction or even damage to server hardware. The user is responsible for any damage to equipment due to improper use of the override parameter. HP expressly disclaims any liability for damage arising from improper use of the override parameter. To confirm the power limits and capabilities of each slot, as well as the entire system, contact the server manufacturer. For information about using the override parameter, contact HP Customer Support.

NOTE: The override parameter overrides the setting that prevents devices from drawing more than 25 W from the PCIe slot. The parameter is enabled by device using the device serial numbers. Once the setting is overridden, each device might draw up to the full 55 W needed for peak performance.

Before you enable the override parameter, ensure that each PCIe slot is rated to provide enough power for all slots, devices, and server accessories. To determine the power slot limits, consult the server documentation, BIOS interface, setup utility, or use the fio-pci-checkcommand.

Important considerations

•If you are installing more than one dual IO Accelerator device and enabling the override parameter for each device, be sure the motherboard is rated to provide 55W power to each slot used. For example, some motherboards safely provide up to 75W to any one slot, but run into power constraints when multiple slots are used to provide that much power. Installing multiple devices in this situation might result in server hardware damage. Consult with the manufacturer to determine the total PCIe slot power available.

•The override parameter persists in the system and enables full power draw on an enabled device even if the device is removed and then placed in a different slot within the same system. If the device is placed

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