From: Goffredo Baroncelli <kreijack@libero.it>
To: Chris Murphy <lists@colorremedies.com>,
Remi Gauvin <remi@georgianit.com>
Cc: DanglingPointer <danglingpointerexception@gmail.com>,
linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: RAID56 Warning on "multiple serious data-loss bugs"
Date: Tue, 29 Jan 2019 20:47:17 +0100 [thread overview]
Message-ID: <80f46e68-4cda-3a22-385b-0ab0a47b079a@libero.it> (raw)
In-Reply-To: <CAJCQCtQ=mGdZ+90uR68hwqFcZaNP8xQwKXkpO395xB+KBXRkxA@mail.gmail.com>
On 29/01/2019 20.02, Chris Murphy wrote:
> On Mon, Jan 28, 2019 at 3:52 PM Remi Gauvin <remi@georgianit.com> wrote:
>>
>> On 2019-01-28 5:07 p.m., DanglingPointer wrote:
>>
>>> From Qu's statement and perspective, there's no difference to other
>>> non-BTRFS software RAID56's out there that are marked as stable (except
>>> ZFS).
>>> Also there are no "multiple serious data-loss bugs".
>>> Please do consider my proposal as it will decrease the amount of
>>> incorrect paranoia that exists in the community.
>>> As long as the Wiki properly mentions the current state with the options
>>> for mitigation; like backup power and perhaps RAID1 for metadata or
>>> anything else you believe as appropriate.
>>
>> Should implement some way to automatically scrub on unclean shutdown.
>> BTRFS is the only (to my knowlege) Raid implementation that will not
>> automatically detect an unclean shutdown and fix the affected parity
>> blocks, (either by some form of write journal/write intent map, or full
>> resync.)
>
> There's no dirty bit set on mount, and thus no dirty bit to unset on
> clean mount, from which to infer a dirty unmount if it's present at
> the next mount.
It would be sufficient to use the log, which BTRFS already has. During each transaction, when an area is touched by a rwm cycle, it has to tracked in the log.
In case of unclean shutdown, it is already implemented a way to replay the log. So it would be sufficient to track a scrub of these area as "log replay".
Of course I am talking as not a BTRFS developers, so the reality could be more complex: e.g. I don't know how it would be easy to raise a scrub process on per area basis.
BR
G.Baroncelli
--
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
next prev parent reply other threads:[~2019-01-29 19:55 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
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 [this message]
2019-01-30 1:41 ` DanglingPointer
2019-02-01 18:45 ` Remi Gauvin
2019-01-29 1:46 ` Qu Wenruo
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