Re: [PATCH 1/4] md: Factor out RAID6 algorithms into lib/

Ric Wheeler
2009-07-17T14:22:11Z

On 07/16/2009 01:38 PM, H. Peter Anvin wrote:
> Dan Williams wrote:
>> On Mon, Jul 13, 2009 at 7:11 AM, David Woodhouse<dwmw2@infradead.org>
>> wrote:
>>> We'll want to use these in btrfs too.
>>>
>>> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
>>
>> Do you suspect that btrfs will also want to perform these operations
>> asynchronously? I am preparing an updated release of the raid6
>> offload patch kit, but the previous WIP release can be browsed at:
>>
>> http://git.kernel.org/?p=linux/kernel/git/djbw/async_tx.git;a=shortlog;h=raid6
>>
>>
>> The routines are housed in crypto/async_tx/async_pq.c and
>> crypto/async_tx/async_raid6_recov.c.
>>
>> I also wonder if the raid6 algos are a better fit under crypto/
>> alongside xor?
>>
>
> I am also sitting on a set of synchronous (CPU) acceleration patches
> for RAID-6 recovery, just waiting for the APIs to stabilize.
>
> -hpa
>

Worth sharing a pointer to a really neat set of papers that describe
open source friendly RAID6 and erasure encoding algorithms that were
presented last year and this at FAST:

http://www.cs.utk.edu/~plank/plank/papers/papers.html

If I remember correctly, James Plank's papers also have implemented and
benchmarked the various encodings,

Ric