Myce/OakGate Reads and Writes Tests
The tests are designed to show the Random and Sequential,
Read and Write, performance metrics for different combinations of Queue Depth
and IO size.
Here are the results –
You can see that performance scales as we increase the Queue
Depth to 128.
You can also see that a Queue Depth of 256 (the theoretical
maximum queue depth for SAS 2.0) gives a poorer result than a Queue Depth of 128.
It looks as if the AL13SXB600N, just as is the case for many SAS SSDs, doesn’t scale
to queue depths greater than 128. We ran a quick test to see where the
degradation starts (the test simply records average IOPS performance for 4K
random reads over 3 minute periods, as queue depth is increased from 128) –
You can see that there is degradation in performance as soon
as the Queue Depth exceeds 128. Please note that this is not showing up a
problem with the drive, I ran this test, just for interest, to see if the
maximum Queue Depth (from a performance perspective on the Oakgate test unit)
lay somewhere between 128 and 256, or whether it was indeed 128.
You can see that for Random 4K Writes there is little or no
scalability above a Queue Depth of 32
As for Random Reads, we see that with Random Writes,
performance degrades for a Queue Depth of 256 compared to a Queue Depth of
128. Again, we ran a simple test which records average IOPS performance over 3
minute periods to observe what happens as we increase Queue Depth over 128 –
We can see that there is degradation in performance as soon
as the Queue Depth is increased over 128.
We can see that for Sequential Reads there is no scalability
above a Queue Depth of 4 (and that there is the now expected degradation in
performance at a Queue Depth of 256).
We can see that Read Bandwidth peaks at just over 230 MB/s,
which compares well with Toshiba’s specification of 228 MB/s.
We can see that IOPS does not vary much as Queue Depth
increases (and that there is the now expected degradation at a queue depth of
Now let’s head to the next page, to look at the results
for the Myce/Oakgate 4K Mixed Reads/Writes Tests…..