Intel DC S3700 Review – a full Performance Characterisation

SNIA Write Saturation Test

Here is the specification for this test –

The objective of this test is
to observe the time evolution of the drive’s performance, as a function of
time, from a ‘factory fresh’, ‘fresh out of the box’ (‘FOB’) state.  When a
drive is in a FOB state (e.g. after it has been purged by, for example by a
SATA Secure Erase), we can expect an initial period of time when writes can
easily be accommodated by clean/empty blocks, but once all of the clean blocks
have been written to once and the drive’s controller must first clean blocks
(with erase write operations) before it can write new data, then we can expect
a slow down.  The slow-down is usually quite dramatic and is commonly referred
to as the ‘write cliff’. 

The Write Saturation Test is
easy to run as it requires no steady state determination – it can be easily run
in freely available software, such as IOMeter.

Here is the report of the
results –


You can see here the decline in Write IOPS performance as
the DC S3700 drops towards a Steady State. The marked fall, at around Round 17,
occurs, I assume, when all of the available NAND has been written to once and
the drive must clean blocks on the fly in preparation for accommodating further
writes – this is commonly referred to as the ‘Write Cliff’.

This is a typical picture of behaviour, and you can see that
the drive is achieving a steady state by Round 63 at around 35,000-36,000 IOPS
(which meets Intel’s spec of up to 36,000)

Note that the test was halted, as specified in the SNIA SSS
PTS, when 4 x the User Capacity had been written to the drive.


You can see here the increase in Write latency as the DC
S3700 drops towards a Steady State.  You can also see that the latency graph line
is a mirror image of the IOPS graph line.


 

This is a graph showing the Maximum Write Latency values
that occurred in each Round.


Now let’s head to the next page, to look at the SNIA
Throughput Test…..