Author Topic: CUDA support would be AWESOME  (Read 2057 times)

Offline almarma

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CUDA support would be AWESOME
« on: February 18, 2014, 01:20:14 pm »
Hello,

It's my first post, I don't even installed FlexRAID in any of my computers, but I'm planing to do it, and while I research for different alternatives, suddenly I thought: is there any softRAID out there that uses a GPU to do the parity checksums? As far as I know, some are investigating it, and I found a nice article explaining the idea:

http://unbeknownst.net/archives/408

As you probably already know, GPUs are much better than CPUs for certain tasks, and maybe this one is one of those, where speed is really important (rebuilding a RAID as fast as possible after a failure is really important).

Just my two cents ;)

By the way, I was about to try unRAID but suddenly discovered Flexraid, and it looks even better, as it runs on a full OS. I hope one day it will run on Mac OS X too ;)

Offline Brahim

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Re: CUDA support would be AWESOME
« Reply #1 on: February 18, 2014, 04:04:47 pm »
And it surfaces again. :)

Offloading to the GPU was planned. This was attempted a few years back when RAID-F was first developed.
Remember that FlexRAID has a modular RAID engine architecture. So, developing a new OpenCL RAID engine is doable but not trivial.

Very few systems intended for NAS purposes will have a decent GPU to offload to. But with many CPUs having embedded graphics, this might call for a revisit.
Add a feature request to bug.flexraid.com and we will see if time permits an implementation.

Note that things won't be all that much faster offloading to the GPU if at all (outside of benchmarks). It is truly a matter of freeing the CPU.

Offline Marv21

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Re: CUDA support would be AWESOME
« Reply #2 on: February 26, 2014, 04:51:06 pm »
Does Traid / Flexraid need so much CPU?
I mean every CPU that have a good gpu has enough power for the parity, or not?


Offline terrastrife

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Re: CUDA support would be AWESOME
« Reply #3 on: February 26, 2014, 05:52:55 pm »
Does Traid / Flexraid need so much CPU?
I mean every CPU that have a good gpu has enough power for the parity, or not?
It's mainly disk bound unless you're using some kind of old mobile single core.

Offline Brahim

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Re: CUDA support would be AWESOME
« Reply #4 on: February 26, 2014, 07:50:16 pm »
Transparent RAID does not need much CPU. However, it can still be good to offload parity computation and free the CPU to other tasks.

RAID-F does use a bit of CPU during it operations. So, offloading that won't be a bad thing either.

The value proposition remains: buy a capable GPU or get a faster CPU.
I think most will choose to get a faster CPU.
Your NAS box should not also be your gaming box. So, those users that have decent GPU on their NAS are going to be few and far in between let alone those from that group that will truly benefit from offloading.

This will basically be a cool feature as opposed to a needed feature.


Offline almarma

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Re: CUDA support would be AWESOME
« Reply #5 on: April 23, 2014, 09:21:44 am »
Thank you very much Brahim for your answers,

Yes, I understand of course your point of view, it has no much sense using a gaming GPU on a storage server that most of the time will run even without a screen.

I just thought, as I've been reading about RAID for years, that parity check and reconstructing a RAID is CPU intensive, and typically takes hours or days, and those that suffered it, can't relax until it's done, because the data is at higher risk during that time. GPUs these days, are incredible powerful, and they discovered that can calculate some things much much faster than CPUs: one of the first thing was video decoding: when GPUs began to do it, video performance in computers got to a new level. And later they made CUDA, to use it even more. These days, for example, Bitcoin farmers use GPU farms to bitcoins mining, because they are extremely more powerful than CPUs for that task.

I don't know yet if tRAID or RAID-f need that power when restoring a damaged over a replacement disk(s). If not, of course, a GPU is not needed at all and that would be good news to make cheaper and more energy efficient servers ;). I love the "KISS" philosophy (Keep It Simple, Stupid), so if it's not needed, it's better to keep it simple: the more simple, the less failure points one can find, the more stable the system is :)

Thanks for your answers again!

Offline Brahim

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Re: CUDA support would be AWESOME
« Reply #6 on: April 23, 2014, 10:41:02 am »
Yeah, it is not needed. RAID-F and tRAID are I/O bound and not CPU bound.

Once I catch a break and feel like playing with things, I might add support for a few CPUs with embedded GPU.
RAID-F and tRAID are designed to have modular RAID engines. So, specialized engines can be plugged in based on interest.