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From: Roberto Spadim <roberto@spadim.com.br>
To: Drew <drew.kay@gmail.com>
Cc: Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: [RFE] Please, add optional RAID1 feature (= chunk checksums) to make it more robust
Date: Mon, 23 Jul 2012 18:42:45 -0300	[thread overview]
Message-ID: <CABYL=TrrQdtfg3gFiXL4Y9QoT9gzNNGnoGUcMN+sxKOH8kGvYQ@mail.gmail.com> (raw)
In-Reply-To: <CACJz6Qu6qVAroTTZJL=Q_Gs5VRsn=VttaKMu0WOKCh2sdJdgqQ@mail.gmail.com>

that´s the point...
in few words....

2012/7/23 Drew <drew.kay@gmail.com>:
> Been mulling this problem over and I keep getting hung up on one
> problem with ECC on a two disk RAID1 setup.
>
> In the event of silent corruption of one disk, which one is the good copy?
>
> It works fine if the ECC code is identical across both mirrors. Just
> checksum both chunks and discard the incorrect one.
nice we can recover data =)

>
> It also works fine if the ECC codes are corrupted but the data chunks
> are identical. Discard the bad checksum.
nice we can recover data too =)

>
> What if the corruption goes across several sectors and both data & ECC
> chuncks are corrupted? Now you're back to square one.
report badblock to upper layer (file system or a mdraid or lvm or
anyother process)
the same should occur on harddisk with known corrupted data
but in this case we know that´s wrong and we can report it! =) that´s
the nice part!
very different from "silent data corruption" where no alert or warning
or error is reported, that´s the today bad part...
ok... you will tell about NEC report? they have this 'software
security' in firmware (i think we could make something similar)


> --
> Drew
>
> "Nothing in life is to be feared. It is only to be understood."
> --Marie Curie
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
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-- 
Roberto Spadim
Spadim Technology / SPAEmpresarial
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  reply	other threads:[~2012-07-23 21:42 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1082734092.338339.1342995087426.JavaMail.root@redhat.com>
2012-07-23  4:29 ` [RFE] Please, add optional RAID1 feature (= chunk checksums) to make it more robust Stan Hoeppner
2012-07-23  9:34   ` Jaromir Capik
2012-07-23 10:53     ` Stan Hoeppner
2012-07-23 17:03     ` Piergiorgio Sartor
2012-07-23 18:24       ` Roberto Spadim
2012-07-23 21:31         ` Drew
2012-07-23 21:42           ` Roberto Spadim [this message]
2012-07-24  4:42           ` Stan Hoeppner
2012-07-24 12:51             ` Roberto Spadim
2012-07-27  6:06           ` Adam Goryachev
2012-07-27 13:42             ` Roberto Spadim
2012-07-24 15:09         ` Jaromir Capik
     [not found] <1897705147.341625.1342995720661.JavaMail.root@redhat.com>
2012-07-23  4:30 ` Stan Hoeppner
     [not found] <17025a94-1999-4619-b23d-7460946c2f85@zmail15.collab.prod.int.phx2.redhat.com>
2012-07-18 11:01 ` Jaromir Capik
2012-07-18 11:13   ` Mathias Burén
2012-07-18 12:42     ` Jaromir Capik
2012-07-18 11:15   ` NeilBrown
2012-07-18 13:04     ` Jaromir Capik
2012-07-19  3:48       ` Stan Hoeppner
2012-07-20 12:53         ` Jaromir Capik
2012-07-20 18:24           ` Roberto Spadim
2012-07-20 18:30             ` Roberto Spadim
2012-07-20 20:07             ` Jaromir Capik
2012-07-20 20:21               ` Roberto Spadim
2012-07-20 20:44                 ` Jaromir Capik
2012-07-20 20:59                   ` Roberto Spadim
2012-07-21  3:58           ` Stan Hoeppner
2012-07-18 11:49   ` keld
2012-07-18 13:08     ` Jaromir Capik
2012-07-18 16:08       ` Roberto Spadim
2012-07-20 10:35         ` Jaromir Capik
2012-07-18 21:02       ` keld
2012-07-18 16:28   ` Asdo
2012-07-20 11:07     ` Jaromir Capik
2012-07-20 11:14       ` Oliver Schinagl
2012-07-20 11:28       ` Jaromir Capik

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