NVMe

What is an SSD Trim Command?

TrimmerAlthough the Trim command has been defined for nearly a decade, for some reason I have never written a post to explain it.  It’s time for that to change.

Trim is something that was never required for HDDs, so it was a new command that was defined once SSDs became prevalent.  The command is required because of one of those awkward encumbrances that NAND users must accommodate: Erase before write.

NAND flash bits cannot be altered the same way as an HDD.  In an HDD a bit that’s currently set to a “1” can be re-written to a “0” and vice versa.  Writing a bit either way takes the same amount of time.  In NAND flash a 1 can be written to a zero, but the opposite is not the case.  Instead, the entire block (4-16k bytes) must be erased at once, after which all bits are set to a 1.  Once that has been done then zeros can be written into that block to store data.  An erase is an excruciatingly slow operation, taking up to a half second to perform.  Writes are faster, but they’re still slow.

Let’s say that a program needs to Continue reading

OCZ Comes Roaring Back with NVMe SSD Debut

The OCZ Z-Drive 6000It’s really something to see a company recover from a big challenge, and signs of that happened this week with OCZ’s introduction of a new NVMe-based PCIe SSD they call the Z-Drive 6000 series.

This replacement for the company’s Z-Drive 4000 series is a complete redesign with an obsession for performance.  OCZ tells me that they moved from a 2-hop design to a 1-hop by using the PMC Princeton PCIe SSD controller, and have passed the University of New Hampshire Interoperability Labs’ compliance tests to NVMe 1.1B compliance.

But how does it perform?  Well the 1-hop design helps reduce latency (which is just starting to overshadow IOPS in users’ minds) and the latency of this SSD is significantly lower than competing NVMe SSDs: between 25-30μs, figures that OCZ tells me are very consistent, a big plus for enterprise applications.  As for IOPS, the device can perform under a 70/30 Read/Write load at 330K.

The 6000 series is provided in both standard MLC and eMLC for those who want the security of eMLC and are willing to sacrifice a little performance to sleep better at night.

This product is a good fit for the market needs, and shows how devoted OCZ and its parent Toshiba are to providing high performance in the SSD marketplace.