We have a limited number of high drive-count systems tested with GbE interfaces. Many of this platform's contemporaries either ship with 10GbE or offer it as an option.
All of the systems in today's review are filled with Seagate NAS 4TB disks in RAID 6, our preference for appliances with six or more drive bays. The QNAP TS-563 is actually a five-bay system, but we ran it in RAID 6 as an extra comparison point. All three contenders run from a single GbE port and through an enterprise switch.
Given what we know about Asustor's typical performance, it doesn't surprise us to see the AS5108T leading our sequential read tests. The system pulls away even more when we measure random read IOPS.
The 128KB and 256KB block sizes are the only two where the AS5108T outperforms its competition when writing sequential data. When we look at 1MB blocks, the AS5108T holds steady at 120 MB/s and doesn't let up.
Asustor is aggressive with its buffers. In our 128KB mixed workload, the AS5108T performs well, and in most read/write mixes outperforms the two QNAP configurations. The 1MB mixed workload goes the other way, where performance drops off as sequential writes are added to the mix. I suspect that the buffer filled, forcing the system to pass cached and incoming data to the eight drives at the same time. This would explain the low performance as write traffic increased.
This set of charts shows why we measure performance in different ways. Reading data from the three systems using various block sizes shows the AS5108T under its QNAP competition.
In the 4KB and 8KB random read tests, where we scale the workload by queue depth, storage behavior changes quickly. Asustor's AS5108T caches the reads and delivers SSD-like random performance. For this to happen under real-world conditions, the repeat rate has to be high. But when you're working with that type of workload, this system truly delivers high random read IOPS without a dedicated SSD for cache.
But as we saw from our sequential write tests, the AS5108T is brought back to Earth when it comes time to write random data. Gone are the explosive random transfers, though the numbers we do measure are still impressive.
Asustor's AS5108T falls in line with many other products when we mix the reads and writes. These three boxes show how difficult it can be to stand out, faced with the limitation of gigabit Ethernet. Ten GbE allows much more separation between appliances.