HP IO Accelerator for BladeSystem c-Class - Manual (Page 10)

Introduction 10
The IO Accelerators (QK761A, QK762A, and QK763A) for Gen 8 BladeSystem c-Class have the power cut
functionality embedded on the card. They offer the protection without requiring the remote power cut module.
NOTE: The Remote Power Cut Module is used only in the AJ878B and BK836A models. Without
the Remote Power Cut Module, write performance is slower.
HP PCIe IO Accelerator minimum requirements
• An open PCI-Express slot—The accelerator requires a minimum of one half-length, half-height slot with
a x4 physical connector. All four lanes must be connected for full performance. HP PCIe IO Accelerator
Duo requires a minimum of a full-height, half-length slot with an x8 physical connection. If your system
is using PCI 1.1, all x8 signaling lanes must be connected for full performance. If your system is using
PCI 2.0, for full performance you only have to connect x4 signaling lanes.
NOTE: For PCIe IO Accelerators, using PCIe slots greater than x4 does not improve
performance.
NOTE: The power cut feature is built into PCIe IO Accelerators; therefore, no Remote Power Cut
Module is necessary.
• 300 LFM of airflow at no greater than 50°C. To protect against thermal damage, the IO Accelerator
also monitors the junction temperature of its controller. The temperature represents the internal
temperature of the controller, and it is reported in fio-status report. The IO Accelerator begins
throttling write performance when the junction temperature reaches 78°C. If the junction temperature
continues to rise, the IO Accelerator shuts down when the temperature reaches 85°C.
NOTE: If you experience write performance throttling due to high temperatures, see your
computer documentation for details on increasing airflow, including fan speeds.
• Sufficient RAM to operate—The amount of RAM that the driver requires to manage the NAND flash
varies according to the block size you select when formatting the device (filesystem format, not low-level
format). For a virtual machine using an IO Accelerator directly (using PCI pass-through), consult the user
guide for the installed operating system. The following table lists the amount of RAM required per
100GB of storage space, using various block sizes. The amount of RAM used in driver version 3.0 is
significantly less than the amount used in version 1.2.x.
Average block size
(bytes) RAM usage for each 80
GB IO Accelerator
(Megabytes)
RAM usage for each 100
GB IO Accelerator
(Megabytes)
Minimum system RAM
requirement for 320 GB
MezzIO Accelerator*
8,192 250 280 1 GB
4,096 400 530 1.6 GB
2,048
750 1,030 3 GB
1,024 1,450 2,000 5.8 GB
512 2,850 3,970 11.4 GB
Average block size
(bytes)
Minimum system RAM
requirement for 640 GB
MezzIO Accelerator*
Minimum system RAM
requirement for 785 GB
MezzIO Accelerator*
Minimum system RAM
requirement for 1.2 TB
MezzIO Accelerator*
8,192 2 GB 2.2 GB 3.4 GB
4,096 3.2 GB 4.2 GB 6.4 GB
2,048
6 GB 8.1 GB 12.4 GB
1,024 11.6 GB 15.7 GB 24 GB