From: Goffredo Baroncelli <kreijack@libero.it>
To: Christoph Anton Mitterer <calestyo@scientia.net>,
linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes
Date: Wed, 2 Aug 2017 00:24:37 +0200 [thread overview]
Message-ID: <c6938d0a-6c63-6dd7-ced4-7ed3b7a3a1e4@libero.it> (raw)
In-Reply-To: <1501621244.5007.2.camel@scientia.net>
On 2017-08-01 23:00, Christoph Anton Mitterer wrote:
> Hi.
>
> Stupid question:
> Would the write hole be closed already, if parity was checksummed?
No.
The write hole problem is due to a combination of two things:
a) misalignment between parity and data (i.e. unclean shutdown)
b) loosing of a disk (i.e. disk rupture)
Note1: the write hole problem happens even if these two event are not consecutive.
After the disk rupture, when you need to read a data from the broken disk, you need the parity to compute the data. But if the parity is misaligned, wrong data is returned.
The data checksum are sufficient to detect if wrong data is returned. The checksum parity is not needed. In any case both can't avoid the problem.
> Cheers,
> Chris.
>
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:[~2017-08-01 22:24 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-01 16:14 [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes Liu Bo
2017-08-01 16:14 ` [PATCH 01/14] Btrfs: raid56: add raid56 log via add_dev v2 ioctl Liu Bo
2017-08-02 19:25 ` Nikolay Borisov
2017-08-01 16:14 ` [PATCH 02/14] Btrfs: raid56: do not allocate chunk on raid56 log Liu Bo
2017-08-01 16:14 ` [PATCH 03/14] Btrfs: raid56: detect raid56 log on mount Liu Bo
2017-08-01 16:14 ` [PATCH 04/14] Btrfs: raid56: add verbose debug Liu Bo
2017-08-01 16:14 ` [PATCH 05/14] Btrfs: raid56: add stripe log for raid5/6 Liu Bo
2017-08-01 16:14 ` [PATCH 06/14] Btrfs: raid56: add reclaim support Liu Bo
2017-08-01 16:14 ` [PATCH 07/14] Btrfs: raid56: load r5log Liu Bo
2017-08-01 16:14 ` [PATCH 08/14] Btrfs: raid56: log recovery Liu Bo
2017-08-01 16:14 ` [PATCH 09/14] Btrfs: raid56: add readahead for recovery Liu Bo
2017-08-01 16:14 ` [PATCH 10/14] Btrfs: raid56: use the readahead helper to get page Liu Bo
2017-08-01 16:14 ` [PATCH 11/14] Btrfs: raid56: add csum support Liu Bo
2017-08-01 16:14 ` [PATCH 12/14] Btrfs: raid56: fix error handling while adding a log device Liu Bo
2017-08-01 16:14 ` [PATCH 13/14] Btrfs: raid56: initialize raid5/6 log after adding it Liu Bo
2017-08-01 16:14 ` [PATCH 14/14] Btrfs: raid56: maintain IO order on raid5/6 log Liu Bo
2017-08-01 16:14 ` [PATCH 1/2] Btrfs-progs: add option to add raid5/6 log device Liu Bo
2017-08-01 16:14 ` [PATCH 2/2] Btrfs-progs: introduce super_journal_tail to inspect-dump-super Liu Bo
2017-08-01 17:25 ` [PATCH 00/14 RFC] Btrfs: Add journal for raid5/6 writes Roman Mamedov
2017-08-01 17:03 ` Liu Bo
2017-08-01 17:39 ` Austin S. Hemmelgarn
2017-08-01 17:07 ` Liu Bo
2017-08-02 18:47 ` Chris Mason
2018-05-03 19:16 ` Goffredo Baroncelli
2017-08-01 17:28 ` Hugo Mills
2017-08-01 16:56 ` Liu Bo
2017-08-01 18:15 ` Hugo Mills
2017-08-01 17:42 ` Goffredo Baroncelli
2017-08-01 17:24 ` Liu Bo
2017-08-01 22:14 ` Goffredo Baroncelli
2017-08-02 17:57 ` Liu Bo
2017-08-02 20:41 ` Goffredo Baroncelli
2017-08-02 20:27 ` Liu Bo
2017-08-03 4:02 ` Duncan
2017-08-03 4:40 ` Goffredo Baroncelli
2017-08-23 15:28 ` Chris Murphy
2017-08-23 15:47 ` Austin S. Hemmelgarn
2017-08-25 13:53 ` Goffredo Baroncelli
2017-08-01 21:00 ` Christoph Anton Mitterer
2017-08-01 22:24 ` Goffredo Baroncelli [this message]
[not found] <CAL5DHTFA8G5fq=BQ7N7qQimesjygKTiBR2qZF4YBRAsAjB_L5Q@mail.gmail.com>
2019-07-30 16:20 ` Goffredo Baroncelli
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