TEST SETUP AND METHODOLOGY
In testing all enterprise drives we focus on long term stability. In doing so, we stress products not only to their maximum rates, but also with workloads suited to enterprise environments. We use many off-the-shelf tests to determine performance, but we also have specialized tests to explore specific behaviors we encounter. With enterprise drives, you will see that we do not focus on many consumer level use-cases.
When testing SSDs, the drive is purged and then preconditioned into a steady state before capturing its performance results. We also disable all write caching on the DUT when possible, this ensures consistent results that are complaint with SNIA standards. Our hope is that we present tangible results that provide relevant information to the buying public.
|PC CHASSIS:||Thermaltake Urban T81|
|MOTHERBOARD:||ASRock X99 WS-E|
|CPU:||Intel Xeon E5-2690 v3|
|CPU COOLER:||Thermaltake Water 3.0 Ultimate|
|POWER SUPPLY:||Thermaltake Toughpower 1500W Gold|
|GRAPHICS:||MSI GT 720
|SYSTEM COOLING:||be quiet! Silent Wings 2|
|MEMORY:||Crucial Ballistix Sport DDR4 2400MHz|
|STORAGE:||Crucial MX200 500GB|
|OS:||Windows Server 2012 R2|
This Test Bench build was the result of some great relationships and purchase; our appreciation goes to those who jumped in specifically to help the cause. Key contributors to this build are our friends at ASRock for the motherboard and CPU, be quiet! for the cooling fans, and Thermaltake for the case. We have detailed all components in the table below and they are all linked should you wish to make a duplicate of our system as so many seem to do, or check out the price of any single component. As always, we appreciate your support in any purchase through our links!
The Storage Networking Industry Association has an entire industry accepted performance test specification for solid state storage devices. Some of the tests are complicated to perform, but they allow us to look at some important performance metrics in a standard, objective way.
SNIA’s Performance Test Specification (PTS) includes IOPS testing, but it is much more comprehensive than just running 4KB writes with Iometer. SNIA testing is more like a marathon than a sprint. In total, there are 25 rounds of tests, each lasting 56 minutes. Each round consists of 8 different block sizes (512 bytes through 1MB) and 7 different access patterns (100% reads to 100% writes). After 25 rounds are finished (just a bit longer than 23 hours), we record the average performance of 4 rounds after we enter steady state.
- Purge: Secure Erase, Format Unit, or vender specific
- Preconditioning: 2x capacity fill with 128K sequential writes
- Each round is composed of .5K, 4K, 8K, 16K, 32K, 64K, 128K, and 1MB accesses
- Each access size is run at 100%, 95%, 65%, 50%, 35%, 5%, and 0% Read/Write Mixes, each for one minute.
- The test is composed of 25 rounds (one round takes 56 minutes, 25 rounds = 1,400 minutes)
Unlike our other performance tests, the SNIA tests only last for a relatively short period of time each (1 minute), but they cover many more access patterns and transfer sizes. All tests were done at a QD of 256. Looking at 100% read performance we can see that overall it is very solid, however, we were unable to achieve the rated 750K IOPS at 4KB under this test series. It was able to still achieve a very respectable result of 631K IOPS. Looking on the opposite end of the scale we can see that it managed to best it’s rated spec for 4K write, reaching 136K IOPS. Also, during the 4KB 65%/35% read/write portion of the test the drive averaged 230K IOPS, which is nearly in line with the stated 250K IOPS for 70%/30% mix.
To specifically measure latency, we use a series of 512b, 4K, and 8K measurements. At each block size, latency is measured for 100% read, 65% read/35% write, and 100% write/0% read mixes.
At QD256 average latency we can see that overall it is very good, especially for the 4KB file size with all results under 1ms. At the 8KB files size the average latency is approximately double at the 65%/35% mix, and less than double at both 100% read and write. Looking at the results from our last Enterprise PCIe SSD review, we can see that this drive maintains a bit lower latency than the 3.2TB HGST SN100.
The XC100’s maximum latency results during 100% reads and 65% reads are not very good. The result of 444ms, 0% read maximum latency shows to be the highest we have yet to see at the 8KB file size. Just as well, at the 0.5 and 4KB file sizes the maximum latency reached 184ms and 193ms respectively.