Monday, November 15, 2010

Sequential READ:    up to 360 / 360 MB/s

Sequential WRITE:     up to 275 / 255 MB/s

Random READ:    up to 60K / 44K IOPs

Random WRITE:    up to 45.2K / 16K IOPs

READ latency:    0.153 / 0.154 ms (TYP)

WRITE latency:    0.118 / 0.424 ms (TYP)

* 128K transfers used for sequential READ/WRITE values, 4K transfers used for random READ/WRITE latency values. All are measured with write cache disabled

Typical I/O performance numbers measured using Iometer with a queue depth of 32 and write cache enabled

What it does

According to Micron, this is the highest performing SATA enterprise SSD in the industry and features the best endurance of any SSD on the market. The P300 is also the only enterprise product supporting a 6 Gb/s SATA interface. SATA is far and away the industry leader in total adoption with over twice the number of server ports sold compared with SAS. (For more information see “SSD Connectivity Options”) However, the SATA-based P300 also works with SAS interfaces for added flexibility.

Why that matters

SSD endurance

Unlike magnetic hard disk drive (HDD) media, NAND flash supports a finite number of WRITE operations, also referred to as Program/Erase (P/E) cycles. This requires a more sophisticated scheme for data layout than HDDs. Called ‘wear leveling’, this process erases data in full sections or blocks, and organizes data writes in order to minimize the number of these erasures required, to extend the life of the NAND substrate. Wear leveling is carried out in the flash controller which, in conjunction with differences in the quality of the substrate itself, produce widely varying useful ‘lifespans’ in the SSD sold by different manufacturers. Micron, unlike most SSD vendors manufactures its own NAND silicon, a factor that directly contributes to the industry leading performance and endurance this product enjoys.

Consistent performance over time

For its Enterprise drives, Micron publishes two numbers for each performance metric. As shown above, these specs refer to READ and WRITE capabilities that SSD storage devices exhibit in two different conditions, which users will see. “Empty” refers to the ‘fresh out of box’ state, and the performance shown is that which the device will exhibit as it’s being filled for the first time. Until an SSD has been filled to capacity, WRITES only include the “Program” and not the “Erase” step so they can be significantly faster. The problem with this spec is that it’s meaningless for the device for most of its useful life, since SSDs will be filled 1000s of times. Because of this, Micron also lists a spec showing device performance in its true steady-state condition - called “Sustained”, where WRITE performance includes the erase cycle as well. Ironically, many SSD vendors only quote “Empty” specs - an appropriate label, when they don’t also include their steady-state performance numbers.

Vertical Integration

Unlike most SSD vendors, Micron designs the key ingredients involved in SSDs from the firmware down to the NAND substrate. This integration ‘from software to silicon’ means Micron doesn’t have to rely on any outside suppliers for components critical to the production process. The result is a more reliable source of supply and a more reliable product. Similar to other electronic component manufacturing, quality control requires comprehensive failure analysis at every step in production. Micron’s vertical integration assures control over the entire production process and increases product reliability. This also means a better understanding of the technology from top to bottom.

A solid channel product

P300 as a product has some significant advantages for the channel. As mentioned above, P300 is the performance and endurance leader and offers the flexibility of a SATA interface at the 6 Gb/s performance point. This means one product should generate substantial interest for a wide variety of use cases, reducing the need for channel partners to carry more SKUs. Micron’s production stability also means one less potential problem for drive distributors to handle, especially for a product that will generate OEM sales volumes. Micron’s ability to do failure analysis ‘down to the NAND’ also means better reliability and a better environment for troubleshooting and corrective action that integration customers expect from OEM suppliers.

Hardware Compatibility Lists (HCL) are used extensively by the integrator and VAR community to make design decisions. For the vendors of storage controllers and other ‘building block’ components, which maintain these HCLs, each manufacturer they include represents a commitment for testing, updates, etc. Micron is a big enough player in the industry to hold one of these ‘front seat’ positions, meaning that channel partners selling the P300 can be confident they and their customers will find Micron’s products included and up-to-date on HCLs from the industry leaders.

SATA interface

In the spinning disk world, SATA isn’t just an interface difference; SATA drives are manufactured differently than SAS drives. They have different components, different performance and different reliability statistics than SAS. In the SSD world, the only real difference between SAS and SATA drives is the interface. And, while that does bring a few implications for users (SAS drives can do port bonding, for example), for the vast majority of users, there won’t be a functional difference. Being a 6 Gb/s SATA drive, the P300 is positioned to fit well in a majority of SSD use cases.

Use cases

In general, SSD technology offers orders of magnitude performance advantages, especially in IOPS, compared with spinning drives. The P300, as a drive form-factor device, is ideal for replacing boot or log file drives in traditional servers or as a low profile drive for blade servers. The 6 Gb/s SATA interface makes it an economical high performance alternative to SAS SSD for enterprise storage tiering applications. But SSD also provides a significant reliability advantage, as there are no moving parts. This combination of performance and reliability makes the P300 ideal as a boot drive for industrial automation and other critical system components that need an embedded drive for longevity to be a true ‘set and forget’ device.

Storage Switzerland’s Take

The Micron P300 addresses challenges to flash based systems that have been hindering adoption. The SATA port selection increases the number of potential servers that the drive could be installed in. The improved endurance and Micron’s vertical integration addresses the concerns over potential reliability. The sustained performance of the drive after initial fill addresses concerns about unpredictable performance.

What more can you say about a solid-state storage product that has the highest performance, the best endurance, the most flexibility and is made by an industry leader, that does every step in the manufacturing process? This is the type of drive needed to bring SSD technology into the mainstream server market and should prompt a significant step forward in overall adoption.

Eric Slack, Senior Analyst