RAID controller based on GPU?

[James]

Another thought in the RAID arena.

RAID parity seems like it would be a highly parallel workload. Something that could be easily optimized to run at blazing speeds on a GPU.

Think about it. a RAID controller that had zero slowdown due to parity overhead, even with many drives in the array. I think it would be something like this that would be needed to support arrays of SSD's without the controller being a (major) bottleneck.

[Nater]

The big problem is that parity calculations that would run well on a GPU has need some serious error correction. The vast majority of GPUs, or everything that isn't Fermi, doesn't support any form of ECC memory. Then you have to consider if sacrificing some of the GPU's primary performance for RAID calculation would be worth it. You would also have to decide if a GPU would perform better than using dedicated ASICs that already work quite well for the job.

Now, if you're talking about the crappy software RAID that runs on most consumer motherboards, that is a different story. Considering that most PCs don't have ECC memory and how slow the CPU is at doing these calculations, I'd say it's a good idea. I remember looking at the RAID 5 write performance of these motherboard-bound RAID chips and it was like 10-15MB/s. Forget about RAID 6 with it's even more complex parity calculations. With a GPU, you could probably do software-based RAID 6.

[James]

Maybe I wasn't being entirely clear. I mean using a GPU as a replacement for the RoC chip onboard high-end RAID controllers. I don't mean simply software RAID being offloaded to the GPU driver stack, but a standard hardware RAID controller that uses a processor similar to a GPU to drastically speed up parity calculations over the current 32-bit RISC processors they are using now.

[Nater]

Assuming it's a relatively small GPU, I could see it. Use eDRAM instead of lots of GDDR for the 'frame buffer'.

[James]

Turns out about a year ago, someone did a proof of concept on this.

They were indeed able to keep basically a software RAID setup using the GPU for the parity creation, and it could keep up full tilt with an array of SSD's.

Prior art is a *****. Guess I won't be getting rich off of this idea.