Random Data Transfer by Size
As a pure storage server, random data makes up only a very small portion of the workload. The closer you push the NAS into an application server role, the more important random data performance becomes.
The SSD cache really takes off here and accelerates random read performance. The performance increase will depend on the cache hit ratio that you can monitor in the operating system software. The monitor is important for tuning the SSD cache with the limited but effective settings.
The SSD cache has a slightly negative effect on random writes outside of 4KB blocks, where it helps performance. With or without the cache, the QNAP TVS-863+ delivers blistering random write performance. QNAP spent a lot of time tuning systems for virtual machine storage. Many VM writes take place at 8KB. The chart shows QNAP's tuning has paid off at that block size.