Benchmarking

With the information from the previous page, we now know the weakness of DRAM-less SSDs, which is random write with relatively small block sizes.

I tested this by sending random 4K block-sized writes to a file of varying size to control the locality of the writes, which should put different levels of stress on the flash translation layer.



Pretty dramatic results! It looks like the drive really likes its writes to stay in a 4 GB area, which gives the best performance results. Beyond that, performance falls off a cliff until it somewhat stabilizes for 40 GB and beyond.

For our synthetic testing on the following pages, I include two sets of data (where relevant):

• Our standard testing, which uses a test area size of 128 GB
• And a smaller test size of 16 GB to show performance with more consumer-oriented workloads (without cherry-picking the best case, like 4 GB or smaller, which a lot of benchmark programs do by default).