One of the most overlooked areas in many enterprise evaluations of storage solutions is the power consumption and the amount of heat the unit generates. Heat generation has to be mitigated via a range of different types of active cooling methods. This constant need to dissipate heat away from the datacenter results in one of the highest ongoing expenses in these environments. Active cooling requires power and lots of it.
For every watt of power consumed in a datacenter there also has to be a redundancy for that power as well. This will provide the datacenter the ability to continue operating during power 'events'. This usually consists of large banks of batteries and generators that can be a very expensive proposition. By limiting the amount of heat introduced into the datacenter the power used for climate control and the redundancy costs of that power are lowered as well.
Power consumption, by both the device itself and the power needed to deal with any heat generation sometimes costs more than the purchase of the unit itself over the devices lifespan. Power and heat generation are significant measurements to take into consideration when making purchasing decisions.
The workload testing for heat generation was conducted at a QD of 128. We tested 128K sequential read and write, along with 512B with the SanDisk ESS Lightning LS 300S. The results displayed are T-Delta to Ambient. This allows for a higher level of accuracy as it accounts for any small variations in room temperature. We did test without any airflow over the HBAs as we are using an open-air bench. This is not wise for normal users, who should adhere to the 200 LFM requirements.
The 9207-8i does generate a few more degrees in temperature across the tested workloads. This is directly in line with the fact that it consumes 9.8W compared to the 7W that the 9211-8i consumes. The few degrees of extra temperature are within an acceptable range considering the massive IOPS and throughput performance improvements.
Watts to IOPS
Overall keeping a low power threshold is the holy grail of high performance enterprise storage. IOPS/Watts is a calculation used to determine the amount of IOPS that are given per Watt of power consumed. Typically, for every watt of power consumed there is also an accompanying increase in heat generated by the device. This creates a vicious cycle of overall power consumption as the additional heat generated must also be cooled.
Measuring the IOPS/Watts for the random performance between the two HBAs keeps things in perspective. Even though the 9207-8i brings massive improvements in IOPS performance, many would consider an increase in the power per watt consumption ratio to be unacceptable.
The 9207-8i actually improves in this measurement, with 71,428 IOPS per watt, taking into consideration that the HBA can reach the rated 700K IOPS. This is more efficient than the 66,386 watts per IOP that the 9211-8i posted in our testing.
The 9207-8i also posts moderate gains in the throughput IOPS to Watts measurement. The 9207-8i gives 3323 IOPS per Watt in our testing, compared to the 9211-8i with 3278 IOPS per Watt.
Overall, the 9207-8i puts forth excellent results with the design of the newer version being more efficient in our measurements.