linux-btrfs.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: DanglingPointer <danglingpointerexception@gmail.com>,
	linux-btrfs@vger.kernel.org
Subject: Re: RAID56 Warning on "multiple serious data-loss bugs"
Date: Mon, 28 Jan 2019 08:52:29 +0800	[thread overview]
Message-ID: <59a60289-1130-27b4-960b-9014fc8d68e8@gmx.com> (raw)
In-Reply-To: <5d7f63b2-d340-7c3a-679b-26e97ac258a6@gmail.com>


[-- Attachment #1.1: Type: text/plain, Size: 1363 bytes --]



On 2019/1/26 下午7:45, DanglingPointer wrote:
> 
> 
> Hi All,
> 
> For clarity for the masses, what are the "multiple serious data-loss
> bugs" as mentioned in the btrfs wiki?
> The bullet points on this page:
> https://btrfs.wiki.kernel.org/index.php/RAID56
> don't enumerate the bugs.  Not even in a high level.  If anything what
> can be closest to a bug or issue or "resilience use-case missing" would
> be the first point on that page.
> 
> "Parity may be inconsistent after a crash (the "write hole"). The
> problem born when after "an unclean shutdown" a disk failure happens.
> But these are *two* distinct failures. These together break the BTRFS
> raid5 redundancy. If you run a scrub process after "an unclean shutdown"
> (with no disk failure in between) those data which match their checksum
> can still be read out while the mismatched data are lost forever."
> 
> So in a nutshell; "What are the multiple serious data-loss bugs?".

There used to be two, like scrub racing (minor), and screwing up good
copy when doing recovery (major).

Although these two should already be fixed.

So for current upstream kernel, there should be no major problem despite
write hole.

Thanks,
Qu

> If
> there aren't any, perhaps updating the wiki should be considered for
> something less the "dramatic" .
> 
> 
> 


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

  parent reply	other threads:[~2019-01-28  0:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-26 11:45 RAID56 Warning on "multiple serious data-loss bugs" DanglingPointer
2019-01-26 12:07 ` waxhead
2019-01-26 14:05   ` Remi Gauvin
2019-01-28  0:52 ` Qu Wenruo [this message]
2019-01-28 15:23   ` Supercilious Dude
2019-01-28 16:24     ` Adam Borowski
2019-01-28 22:07   ` DanglingPointer
2019-01-28 22:52     ` Remi Gauvin
2019-01-29 19:02       ` Chris Murphy
2019-01-29 19:47         ` Goffredo Baroncelli
2019-01-30  1:41           ` DanglingPointer
2019-02-01 18:45         ` Remi Gauvin
2019-01-29  1:46     ` Qu Wenruo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=59a60289-1130-27b4-960b-9014fc8d68e8@gmx.com \
    --to=quwenruo.btrfs@gmx.com \
    --cc=danglingpointerexception@gmail.com \
    --cc=linux-btrfs@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).