Storage Bench v1.0: Real-World Analysis
Real-World Analysis
We're going to kick off our analysis of the RevoDrive 3 X2 using Storage Bench v1.0 because it allows us to examine the real performance of an SSD within the first two weeks of use.
Storage Bench v1.0 involves two time-oriented metrics in addition to speed: busy and service time.
- Busy time is the total time a drive has an operation in progress.
- Service time is a little different. The total service time for the three operations in the diagram is 1785 s, which is longer than the busy time, because the operations are queued three-deep.
Service time gives more weight to periods of high queue depth (QD), while busy time gives more weight to periods of low queue depth. If you're a desktop user, busy time is a more relevant measure because you're less likely to be running workloads that impose a high queue depth.
How do we know that you should be looking at numbers that represent a low queue depth, rather than high-depth numbers most SSD vendors use to reflect peak performance? Look at the distributions of QDs in Storage Bench v1.0 in the chart below.
If you're using a hard drive or an entry-level SSD, you're more likely to encounter queue depths between two and five. But if you're using a mainstream or performance-oriented SSD, you'll mostly see a queue depth of one. This is because operations complete so much faster on a higher-end SSD that they don't have an opportunity to stack up.
Now, in the case of OCZ's RevoDrive 3 X2, the company expects you to use a vastly different usage model. This isn't a device you buy to browse the Web or compose email. It boasts high potential sequential throughput and random I/O performance, so it's best-suited to tasks that push either or both specifications.
As a result, what we'll see from this more day-to-day trace is how the RevoDrive 3 performs in relation to competing SSDs in a workload that reflects an average user.
Busy time and average data rate are directly tied to one another, but looking at both allows us to examine performance in a slightly different way. Even though we're examining performance at a lower queue depth than where the RevoDrive 3 optimally runs, it still sits at the head of the pack. It's 16% faster than a single 240 GB Vertex 3 and 25% times faster than the original RevoDrive X2.
If this is how you use your computer, the takeaway is that a single 240 GB Vertex 3 is ample to satisfy.
With an average data rate of 226.9 MB/s, the RevoDrive 3 X2 takes performance to the max. The Vertex 3 falls in a close second at 190.7 MB/s, 35 MB/s behind.
