From: Torsten Bronger <bronger@physik.rwth-aachen.de>
To: linux-btrfs@vger.kernel.org
Subject: Re: Why is converting from RAID1 to single in Btrfs an I/O-intensive operation?
Date: Tue, 21 Feb 2023 08:18:14 +0100 [thread overview]
Message-ID: <87r0ujbi6h.fsf@physik.rwth-aachen.de> (raw)
In-Reply-To: 0282b6d0-b131-3b3a-084d-8c8de2f522a5@tnonline.net
Hallöchen!
Forza writes:
> [...]
>
> I believe this would violate the "CoW" nature of Btrfs. In other
> words, it would introduce a change in-place, which is not possible
> with current current way of working.
>
> There probably are ways to make it safe and atomic, but maybe not
> a high priority from the current devs?
My naive assumption was: There is the bulk data, and there is
metadata that also contains the profile of the data. If the profile
is changed, only the metadata has to be re-written atomically (in
particular, the CoW way).
But apparently, the profile is part of the bulk data chunk itself.
This may well be necessary, but I was surprised by that.
Regards,
Torsten.
--
Torsten Bronger
next prev parent reply other threads:[~2023-02-21 7:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-18 8:10 Why is converting from RAID1 to single in Btrfs an I/O-intensive operation? Torsten Bronger
2023-02-18 8:54 ` Andrei Borzenkov
2023-02-18 11:32 ` Torsten Bronger
2023-02-18 10:46 ` Goffredo Baroncelli
2023-02-18 11:38 ` Torsten Bronger
2023-02-18 17:47 ` me
2023-02-18 20:05 ` Torsten Bronger
2023-02-18 21:46 ` me
2023-02-19 10:09 ` Goffredo Baroncelli
2023-02-19 19:04 ` Torsten Bronger
2023-02-19 23:39 ` waxhead
2023-02-20 6:31 ` Torsten Bronger
2023-02-20 9:38 ` Patrik Lundquist
2023-02-20 15:48 ` Forza
2023-02-21 7:18 ` Torsten Bronger [this message]
2023-02-21 11:35 ` me
2023-02-22 8:30 ` Torsten Bronger
2023-02-26 18:52 ` Ferry Toth
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