From: Phillip Susi <phill@thesusis.net>
To: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Cc: Qu Wenruo <quwenruo.btrfs@gmx.com>,
Jan Ziak <0xe2.0x9a.0x9b@gmail.com>,
linux-btrfs@vger.kernel.org
Subject: Re: Btrfs autodefrag wrote 5TB in one day to a 0.5TB SSD without a measurable benefit
Date: Tue, 15 Mar 2022 14:28:46 -0400 [thread overview]
Message-ID: <87fsnjnjxr.fsf@vps.thesusis.net> (raw)
In-Reply-To: <Yi/I54pemZzSrNGg@hungrycats.org>
Zygo Blaxell <ce3g8jdj@umail.furryterror.org> writes:
> btrfs extents are immutable, so the filesystem can't extend an existing
> extent with new data. Instead, a new extent must be created that contains
> both the old and new data to replace the old extent. At least one new
Wait, what? How is an extent immutable? Why isn't a new tree written
out with a larger extent and once the transaction commits, bam... you've
enlarged your extent? Just like modifying any other data.
And do you mean to say that before the new data can be written, the old
data must first be read in and moved to the new extent? That seems
horridly inefficient.
next prev parent reply other threads:[~2022-03-15 18:34 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-06 15:59 Btrfs autodefrag wrote 5TB in one day to a 0.5TB SSD without a measurable benefit Jan Ziak
2022-03-07 0:48 ` Qu Wenruo
2022-03-07 2:23 ` Jan Ziak
2022-03-07 2:39 ` Qu Wenruo
2022-03-07 7:31 ` Qu Wenruo
2022-03-10 1:10 ` Jan Ziak
2022-03-10 1:26 ` Qu Wenruo
2022-03-10 4:33 ` Jan Ziak
2022-03-10 6:42 ` Qu Wenruo
2022-03-10 21:31 ` Jan Ziak
2022-03-10 23:27 ` Qu Wenruo
2022-03-11 2:42 ` Jan Ziak
2022-03-11 2:59 ` Qu Wenruo
2022-03-11 5:04 ` Jan Ziak
2022-03-11 16:31 ` Jan Ziak
2022-03-11 20:02 ` Jan Ziak
2022-03-11 23:04 ` Qu Wenruo
2022-03-11 23:28 ` Jan Ziak
2022-03-11 23:39 ` Qu Wenruo
2022-03-12 0:01 ` Jan Ziak
2022-03-12 0:15 ` Qu Wenruo
2022-03-12 3:16 ` Zygo Blaxell
2022-03-12 2:43 ` Zygo Blaxell
2022-03-12 3:24 ` Qu Wenruo
2022-03-12 3:48 ` Zygo Blaxell
2022-03-14 20:09 ` Phillip Susi
2022-03-14 22:59 ` Zygo Blaxell
2022-03-15 18:28 ` Phillip Susi [this message]
2022-03-15 19:28 ` Jan Ziak
2022-03-15 21:06 ` Zygo Blaxell
2022-03-15 22:20 ` Jan Ziak
2022-03-16 17:02 ` Zygo Blaxell
2022-03-16 17:48 ` Jan Ziak
2022-03-17 2:11 ` Zygo Blaxell
2022-03-16 18:46 ` Phillip Susi
2022-03-16 19:59 ` Zygo Blaxell
2022-03-20 17:50 ` Forza
2022-03-20 21:15 ` Zygo Blaxell
2022-03-08 21:57 ` Jan Ziak
2022-03-08 23:40 ` Qu Wenruo
2022-03-09 22:22 ` Jan Ziak
2022-03-09 22:44 ` Qu Wenruo
2022-03-09 22:55 ` Jan Ziak
2022-03-09 23:00 ` Jan Ziak
2022-03-09 4:48 ` Zygo Blaxell
2022-03-07 14:30 ` Phillip Susi
2022-03-08 21:43 ` Jan Ziak
2022-03-09 18:46 ` Phillip Susi
2022-03-09 21:35 ` Jan Ziak
2022-03-14 20:02 ` Phillip Susi
2022-03-14 21:53 ` Jan Ziak
2022-03-14 22:24 ` Remi Gauvin
2022-03-14 22:51 ` Zygo Blaxell
2022-03-14 23:07 ` Remi Gauvin
2022-03-14 23:39 ` Zygo Blaxell
2022-03-15 14:14 ` Remi Gauvin
2022-03-15 18:51 ` Zygo Blaxell
2022-03-15 19:22 ` Remi Gauvin
2022-03-15 21:08 ` Zygo Blaxell
2022-03-15 18:15 ` Phillip Susi
2022-03-16 16:52 ` Andrei Borzenkov
2022-03-16 18:28 ` Jan Ziak
2022-03-16 18:31 ` Phillip Susi
2022-03-16 18:43 ` Andrei Borzenkov
2022-03-16 18:46 ` Jan Ziak
2022-03-16 19:04 ` Zygo Blaxell
2022-03-17 20:34 ` Phillip Susi
2022-03-17 22:06 ` Zygo Blaxell
2022-03-16 12:47 ` Kai Krakow
2022-03-16 18:18 ` Jan Ziak
-- strict thread matches above, loose matches on Subject: below --
2022-06-17 0:20 Jan Ziak
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