Next-gen OCZ PCIe SSD offers new twist on RAID

At the Consumer Electronics Show earlier this month, we caught our first glimpse of OCZ's third-generation Z-Drive PCIe SSD. The card has a PCI Express 2.0 x8 link and no fewer than four SandForce SF-1565 controllers, each backed by its own array of flash memory chips. At the time, OCZ wouldn't reveal how the SandForce controllers were linked. Previous Z-Drives have used RAID controllers that configured the onboard SSDs in a RAID 0 array. The Z-Drive R3 does things a little differently, though.

Rather than using a traditional RAID controller, the R3 features proprietary Virtualized Controller Architecture (VCA) technology. OCZ's VCA FAQ is a little short on details covering how the technology works, but it appears to be different from RAID and very much SSD-specific. Solid-state drives achieve their impressive performance by accessing multiple flash chips in parallel. RAID controllers are similar in that they extract additional performance by accessing multiple drives at the same time. However, RAID chips can't see the individual flash dies sitting behind an SSD controller. VCA, it seems, can.

According to OCZ, "VCA is able to address NAND flash in an innovative way through the use of a massively parallel array." VCA would require some cooperation from the flash controllers if it wanted to access individual dies directly, but that doesn't seem unreasonable given how closely SandForce and OCZ have been working together.

OCZ says that VCA can eliminate bottlenecks and improve performance. Even more interesting is the fact that it supports TRIM, which doesn't work for solid-state members of traditional RAID arrays. That feature alone gives VCA intriguing potential outside of enterprise-oriented PCIe RAID cards.

Tip: You can use the A/Z keys to walk threads.
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