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Micron RealSSD P320h Review: A PCIe Drive Capable Of 3.2 GB/s

Micron's Firmware And Monitoring Software

As we mentioned on the previous page, the 700 GB RealSSD P320h actually has 1 TB of on-board SLC NAND. Not all of the unaccounted-for memory is used for over-provisioning, as you might expect. Rather, Micron's RAIN (Redundant Array of Independent NAND) technology takes up 128 GB (12.5%). From there, the company imposes ~22% of total capacity for over-provisioning. This takes the total usable capacity down to ~650 GB. 

RAIN is a way of creating parity at the logical storage unit level. Stated most simply it's a 7+1 RAID 5 configuration. For every seven blocks that are written, a single parity element is calculated.

This calculation is done in hardware, in real-time, and in the background, requiring no user/application interaction. Beyond ECC, which the P320h also supports, RAIN allows the card to recover from physical NAND failures. If there is problem, the P320h logs that event and makes it viewable by way of the RealSSD Manager. You can also communicate with the P320h through a fully-featured CLI application.

The RealSSD Manager is a nice tool that allows system administrators to quickly check the health of the drive without creating custom scripts or memorizing cryptic command line switches. Not only can you view the typical SMART (Self Monitoring and Analysis Reporting Technology) parameters, but you can also view live performance stats, media wear, and thermal readings.