These tests are designed to show performance metrics for
different combinations of Queue Depth and Entropy % (Entropy % is the degree to
which the data is random and therefore incompressible). Testing with different
Entropy % levels has become important with the advent of controllers, such as
those from LSI Sandforce, that compress data before writing it to NAND.
Controllers that compress data can be expected to perform better with highly
compressible data (i.e. data with low Entropy).
test performs 5 minutes of Random 4K writes for each combination of Queue Depth
and Entropy %.
test does the same thing for a mixture of Read and Write traffic (70% Reads,
4K Entropy Write Test
You can see there is little or no variance in performance to
be found in any of the Entropy tests, as the degree of random data increases
(and this comment applies to all of the test results for the Myce/OakGate
Entropy Tests). We can therefore conclude that the Seagate 1200 does not
4K Entropy 70% Reads 30% Writes
As we saw no
evidence of compression in the 4K Entropy Write Test we skip the presentation
of the 70/30 entropy results.
head to the next page, to look at Power Consumption and Data Reliability…..