4K Random Read/Write
We precondition the SanDisk 256GB X210 for 18,000 seconds, or five hours, receiving reports on several parameters of workload performance every second. We then plot this data to illustrate the drives' descent into steady state.
This chart consists of 36,000 data points. The lines through the data scatter are the average during the test. This type of testing presents standard deviation and maximum/minimum I/O in a visual manner. We provide histograms for further latency granularity below. This downward slope of performance happens very few times in the lifetime of the device, typically during the first few hours of use.
The 20% of extra overprovisioning (80% LBA) yields a tremendous return in performance, with the heavy random write workload more than tripling in average speed.
Each QD for every parameter tested includes 300 data points (five minutes of one second reports) to illustrate the degree of performance variability. The line for each QD represents the average speed reported during the five-minute interval.
4K random speed measurements are an important metric when comparing drive performance, as the hardest type of file access for any storage solution to master is small-file random. One of the most sought-after performance specifications, 4K random performance is a heavily marketed figure.
The X210 delivers an increase in random read speed from the addition of overprovisioning (OP), which is not an entirely expected result. The increase in random write performance is expected, but the jump in random read speed is a nice surprise. With a standard configuration (100% LBA), the X210 averages 41,826 IOPS, while the extra spare area (80% LBA) provides 68,903 IOPS at QD256.
Garbage collection routines are more pronounced in heavy write workloads. This leads to more variability in performance. The X210 averages 3,871 IOPS in standard configuration, and more than triples that to 15,908 with extra OP. There is the introduction of significant variability with the OP, but this is still better when you are operating at three times the speed of the normal configuration.
Our write percentage testing illustrates the varying performance of each solution with mixed workloads. The 100% column to the right is a pure write workload of the 4K file size, and 0% represents a pure 4K read workload.
The true test of any storage solution is how well it handles mixed read/write operations. The X210 delivers the same large increase in performance across the board with extra OP.
The X210 experiences significantly better latency with the extra overprovisioning. We note the larger distribution of latency results, due to the increased performance variability with extra overprovisioning.
We record the power consumption measurements during our precondition run. We calculate the stated average results during the last five minutes of the test, after the device has settled into steady state.
The X210 draws a very consistent line of 2.32 Watts when accessing 100% of the LBA, but the extra OP introduces some jitter into the results. The jitter does not equate to an overall higher power draw for overprovisioning, the average of 2.42 is still within .1 Watts of the 100% LBA test.
IOPS to Watts measurements are generated from data recorded during our precondition run, and the stated average is from the last five minutes of the test.
When only accessing 80% of the drive (20% OP), the X210 experiences a massive jump in efficiency with an increase from 1,673 to 6,302 IOPS per Watt. For heavy workloads, an efficiency increase of nearly 4X is simply extraordinary.