From: Christoph Hellwig <hch@infradead.org>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Christoph Hellwig <hch@infradead.org>,
Gerhard Wiesinger <lists@wiesinger.com>,
linux-ext4@vger.kernel.org
Subject: Re: Transparent compression with ext4 - especially with zstd
Date: Wed, 22 Jan 2025 06:11:55 -0800 [thread overview]
Message-ID: <Z5D8q3QtpNiGSo22@infradead.org> (raw)
In-Reply-To: <20250122131912.GA3844227@mit.edu>
On Wed, Jan 22, 2025 at 08:19:12AM -0500, Theodore Ts'o wrote:
> ... but out of place writes means that every single fdatasync() called
> by the database now requires a file system level transaction commits.
Yes.
> So now every single fdatasync(2) results in the data blocks getting
> written out to a new location on disk (this is what out of place
> writes mean), followed by a CACHE FLUSH, followed by the metadata
> updates to point at the new location on the disk, first written to the
> file system tranaction log, followed by the fs commit block, followed
> by a *second* CACHE FLUSH command.
Or you put the compressed data in the log and have a single FUA
write.
next prev parent reply other threads:[~2025-01-22 14:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-19 14:37 Transparent compression with ext4 - especially with zstd Gerhard Wiesinger
2025-01-21 4:01 ` Theodore Ts'o
2025-01-21 9:42 ` Artem Blagodarenko
2025-01-21 18:47 ` Gerhard Wiesinger
2025-01-21 19:33 ` Theodore Ts'o
2025-01-22 0:19 ` Kiselev, Oleg
2025-01-22 6:10 ` Gerhard Wiesinger
2025-01-22 7:29 ` Gerhard Wiesinger
2025-01-22 7:37 ` Christoph Hellwig
2025-01-22 13:19 ` Theodore Ts'o
2025-01-22 14:11 ` Christoph Hellwig [this message]
2025-01-21 21:26 ` Dave Chinner
2025-01-22 6:47 ` Gerhard Wiesinger
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