Enterprise Video Streaming Performance
As we know, enterprise customers have different requirements and expectations of their storage than even desktop enthusiasts. If a consumer drive demonstrates periodic performance dips, most users don't perceive the difference. Photoshop may load a few milliseconds slower, or a file finishing copying one second later. In the enterprise video sector, though, large block performance is critical, and even small performance hiccups can cause major issues.
In many streaming applications, you are getting data from a physical device, which could be a digital frame grabber, and writing it to disk. If the disk can't keep up, the data still has to go somewhere. If it can't get to the drive at a specified rate, buffers overflow and data is lost. Ideally, the acquired data would DMA from the device into host memory, and then down to disk. But in the real world, you need buffers. Their size and location can vary greatly based on the application. This section of our story helps show how much buffer allocation is needed for a specific data rate.
Reviews (this one included) give you lots of data designed to demonstrate performance in a number of different scenarios, with the idea that at least some will be relevant to you. The main drawback is that, by going wide, you end up with averages or small sample sizes. Here, we're using the 800 GB SSD 910 in Maximum Performance mode, getting into a steady state, and writing the full capacity 100 times in a row. Each test consists of 8 MB sequential writes with a queue depth of four. Each point on the graph is a 100-point average of the individual 8 MB writes. We'd give you the chart without averages, but Excel does care for 95 000 data points.
The graph below shows the best and worst runs out of all 100 iterations.
If you don't know any better, that might look bad. But it really isn't. Intel's SSD 910 actually does a really good job of maintaining its performance across the entire disk. The table below shows estimated buffer sizes.
| Setpoint (MB/s) | Best-Case Buffer Size In MB | Worst-Case Buffer Size In MB |
|---|---|---|
| 1350 | 23 | 28 |
| 1400 | 24 | 100 |
| 1450 | 33 | 646 |
| 1500 | 46 | 2520 |
| 1550 | 65 | 6729 |
The Intel SSD 910 can easily sustain 1400 MB/s with only a minimal amount of buffering (100 MB). If you go much beyond that, you need to seriously look into allocating multiple gigabytes of memory in order to sustain higher data rates.
The average speed across the entire drive during the best- and worst-case iterations was 1568 and 1536 MB/s, respectively. Even though the difference was 2%, there were a number of other runs with the same deltas that did not show the same drastically different buffer requirements.
