Sequential Data Transfer by Size
In the coming weeks we will detail our extensive testing process and share how we configure systems. In today's review we're comparing the QNAP TVS-863+ to two other products on the market. We are also testing the QNAP TVS-863+ with and without SSD cache-enabled.
Without SSD cache, the TVS-863+ uses eight Seagate NAS hard-disk drives and 10GbE connectivity back to the network. For the SSD cache test we used a SanDisk Extreme PRO 240GB SSD as the cache device and seven Seagate NAS hard disk drives. We configured the SSD cache with the default settings that omit sequential reads and writes but accelerate random data. All QNAP tests were run with the EXT4 file system and RAID 6 for dual redundancy.
For comparison products, we chose the ASUSTOR AS5108T, an 8-bay solution without 10GbE. This system uses the EXT4 file system. The 10GbE comparison product is the Netgear ReadyNAS 716X with six drive bays and the BTRFS (B-tree File System). Both the AS5108T and ReadyNAS 716X were tested in RAID 6 to match the QNAP TVS-863+.
To start the testing portion of the review, we swept sequential block sizes from small to large to see the throughput scaling and find peak QD1 performance. This test also shows us that with the default settings, the QNAP cache algorithm doesn't waste time with sequential data. Users can uncheck a box in the setup procedure to cache sequential data, but most users will not run the system that way.
Here we perform the same type of test-writing data instead of reading it. Again, the cache-enabled test doesn't show a difference, as expected. The QNAP TVS-863+ does show a dip in the performance curve at 128KB, the standard measurement block size for sequential data. In our testing we also show sequential performance with 1MB block sizes as well, so the dip will only affect half of our sequential tests.