From: Alex Elsayed <eternaleye@gmail.com>
To: ceph-devel@vger.kernel.org
Subject: Re: Erasure code library summary
Date: Tue, 18 Jun 2013 18:14:26 -0700 [thread overview]
Message-ID: <kpr0ld$3cr$2@ger.gmane.org> (raw)
In-Reply-To: kpr0dn$3cr$1@ger.gmane.org
Alex Elsayed wrote:
> Loic Dachary wrote:
>
>> Hi Ceph,
>>
> <snip>
>> Reed-Solomon coding family is the only one that can keep the chuncks
>> unencoded and therefore concatenable.
> <snip>
>
> In my understanding, this is not strictly true - any 'systematic' code
> will have the unencoded chunks remain available in this manner, and any
> non- systematic linear code can be transformed into a systematic code with
> the same minimum distance. Fountain codes are often explicitly constructed
> to maintain this property, as in the case of RaptorQ [RFC 6330].
>
> https://en.wikipedia.org/wiki/Systematic_code
...that said, Reed-Solomon is to the best of my knowledge the only space-
optimal such code. An interesting option, however, might be to use a
fountain code over the network when distributing either replicas *or* parity
chunks, so that losses can be recovered with <1 full chunk retransmission.
next prev parent reply other threads:[~2013-06-19 1:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-18 12:22 Erasure code library summary Loic Dachary
2013-06-19 1:10 ` Alex Elsayed
2013-06-19 1:14 ` Alex Elsayed [this message]
2013-06-19 7:00 ` Loic Dachary
2013-06-19 7:47 ` Alex Elsayed
2013-06-19 8:33 ` Loic Dachary
2013-06-19 9:09 ` Alex Elsayed
2013-06-19 10:41 ` Loic Dachary
2013-06-19 6:56 ` Loic Dachary
2013-06-19 11:33 ` Mark Nelson
2013-06-19 12:10 ` Loic Dachary
2013-06-19 12:33 ` Mark Nelson
2013-06-23 7:01 ` Loic Dachary
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