Toshiba HK4E SATA 1600GB Enterprise SSD Review

Power Consumption and Data Reliability

Power Consumption

I believe most people know that data centres are already one
of the major consumers of electricity in the industrialised world; indeed it is
estimated that currently 2% of all electricity consumption goes into IT
applications.  According to the European Union the energy consumption of data
centres was 46 Terawatt hours in 2006 and is set to rise to 93 TW hrs by 2020. This
is equivalent to one hundred million 100W light bulbs burning 24 hours a day,
365 days a year.

Typically 40% of the power consumed by data centres is for
the IT load and 35% is for cooling the system.  Generally speaking, if a drive
consumes more power it will produce more heat – so power consumption is indeed
a double edged sword.  It is no surprise then that a significant proportion of
a data centre’s power consumption goes on servers.  I understand cloud based
applications, such as Facebook, are the primary cause of the growth in servers
and the demand for storage space.

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Power Testing

We present our standard set of power consumption tests.

SNIA Write Saturation

Toshiba HK4E SATA 1600GB Enterprise SSD Review

 

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This test allows us to observe the power consumption
characteristics as the drive passes from a fresh ‘out of the box’ state to one
where blocks must first be cleaned before they can be written to. 


4K Latency Test – Reads

Toshiba HK4E SATA 1600GB Enterprise SSD Review

This test allows us to observe how power consumption
characteristics vary as the demand for Random 4K Reads (in terms of IOPS) is
increased.  You can see that the demand for power increases gradually and in a
linear fashion. 

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As the boost in power consumption rises more slowly than the
increase in IOPS we know intuitively that the sweet spot in regard to IOPS per
mW is at the drive’s highest IOPS level.

 


4K Latency – Writes

Toshiba HK4E SATA 1600GB Enterprise SSD Review

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This test allows us to observe how power consumption
characteristics vary as the demand for Random 4K writes (in terms of IOPS) is
increased.  You can see that the demand for power increases gradually and in a
linear fashion.

 


4K Mixed Reads/Writes

Here are the results, taken from the Myce/OakGate Mixed
Reads/Writes tests –

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Toshiba HK4E SATA 1600GB Enterprise SSD Review

There is no
doubt that the Toshiba uses a lot of power, but what is really important is the
power efficiency, so let’s have a closer look.

We have taken the data to calculate the IOPS per mW for each
combination, as follows –

Toshiba HK4E SATA 1600GB Enterprise SSD Review

 

Now let’s compare these results to the best results we have
seen from a currently competitive drive prior to this review. These are for a Samsung
SM863 480GB –

Toshiba HK4E SATA 1600GB Enterprise SSD Review

 

You can see that the results are similar but that the Toshiba
is more power efficient, especially for the higher Write % values.

 

 


Sequential Reads

Toshiba HK4E SATA 1600GB Enterprise SSD Review

This test allows us to see how power consumption
characteristics vary when performing sequential reads with different combinations
of IO Size and queue depth.  As might be expected, the power consumption
increases as the MB/s increases.

We have then
used this data to calculate the MB/s per mW as follows –

Toshiba HK4E SATA 1600GB Enterprise SSD Review

 

The MB/s per mW results can then be compared to those for
the Samsung SM863 480GB –

Toshiba HK4E SATA 1600GB Enterprise SSD Review

You can see that the results are remarkably similar and both
drives have excellent sequential read efficiency.

 


Sequential Writes

Toshiba HK4E SATA 1600GB Enterprise SSD Review

 

We have then used this data to calculate the MB/s per mW as
follows –

Toshiba HK4E SATA 1600GB Enterprise SSD Review

 

The MB/s per mW results can then be compared to those for
the Samsung SM863 –

Toshiba HK4E SATA 1600GB Enterprise SSD Review

You can see the results are similar but that the Samsung is
largely more efficient for Sequential Writes.


Data Reliability

The ‘Unrecoverable Bit Error Rate’ (UBER),as defined by
JEDEC, the global leader in developing open standards for the microelectronic
industry, is a metric for data corruption rate equal to the number of data
errors per bit read after applying any specified error correction method. UBER
= number of data errors / number of bits read.  JDEC specifies that the maximum
error rate allowable for an Enterprise level SSS solution is one error in every
10^16 bits read.

Unfortunately Toshiba does not specify an UBER for the HK4E
series.

The drive includes Power Loss
Protection to ensure no data is lost in the event of a power failure.

The Toshiba HK4E series is
warranted to perform 3 DWPD (Drive Writes per Day) for 5 years.

 

Now let’s head to the next page, to look at the
Conclusions of this review…..

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