Git Mailing List Archive on lore.kernel.org
 help / color / Atom feed
From: Theodore Ts'o <tytso@mit.edu>
To: Junio C Hamano <gitster@pobox.com>
Cc: Stefan Beller <sbeller@google.com>,
	git@vger.kernel.org, peff@peff.net,
	torvalds@linux-foundation.org
Subject: Re: [PATCH] Enable core.fsyncObjectFiles by default
Date: Tue, 23 Jun 2015 19:29:21 -0400
Message-ID: <20150623232921.GB14324@thunk.org> (raw)
In-Reply-To: <xmqqpp4maww7.fsf@gitster.dls.corp.google.com>

The main issue is that non-expert users might not realize that they
really need to run "git fsck" after a crash; otherwise, what might
happen is that although git is only appending, that you might have
some zero-length (or partially written) git object or pack files, and
while you might not notice at that moment, it might come and bite you
later.  If you do try to recover immediately after a crash, in the
worst case you might have to do that "git am -s /tmp/mbox-filled-with
patches" command, but otherwise you won't lose much data.

So perhaps one alternative strategy to calling fsync(2) after every
single git object file write might be to have git create a zero-length
".git/in-progress-<pid>" file, which gets fsync'ed, and then it can do
the "git am -s /tmp/akpm-big-bag-o-patches" processing nice and fast,
and once git is done, then we call call sync(2) and then delete the
in-progress file.

If there is an in-progress file in the .git directory, git would then
automatically run git fsck to make sure the repository is consistent.

For people who care, maybe that's a good compromise.  (Me, the way
things are right now is just fine since I have a nice fast SSD, and so
setting fsyncObjectfiles is a perfectly fine thing as far as I am
concerned. :-)

		      		     	   - Ted

  reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-23 21:57 Stefan Beller
2015-06-23 22:21 ` Junio C Hamano
2015-06-23 23:29   ` Theodore Ts'o [this message]
2015-06-24  5:32     ` Junio C Hamano
2015-06-24 14:30       ` Theodore Ts'o
2015-06-24  1:07 ` Duy Nguyen
2015-06-24  3:37 ` Jeff King
2015-06-24  5:20   ` Junio C Hamano
2018-01-17 18:48 [PATCH] enable " Christoph Hellwig
2018-01-17 19:04 ` Junio C Hamano
2018-01-17 19:35   ` Christoph Hellwig
2018-01-17 20:05     ` Andreas Schwab
2018-01-17 19:37   ` Matthew Wilcox
2018-01-17 19:42     ` Christoph Hellwig
2018-01-17 21:44   ` Ævar Arnfjörð Bjarmason
2018-01-17 22:07     ` Linus Torvalds
2018-01-17 22:25       ` Linus Torvalds
2018-01-17 23:16       ` Ævar Arnfjörð Bjarmason
2018-01-17 23:42         ` Linus Torvalds
2018-01-17 23:52       ` Theodore Ts'o
2018-01-17 23:57         ` Linus Torvalds
2018-01-18 16:27           ` Christoph Hellwig
2018-01-19 19:08             ` Junio C Hamano
2018-01-20 22:14               ` Theodore Ts'o
2018-01-20 22:27                 ` Junio C Hamano
2018-01-22 15:09                   ` Ævar Arnfjörð Bjarmason
2018-01-22 18:09                     ` Theodore Ts'o
2018-01-23  0:47                       ` Jeff King
2018-01-23  5:45                         ` Theodore Ts'o
2018-01-23 16:17                           ` Jeff King
2018-01-23  0:25                     ` Jeff King
2018-01-21 21:32             ` Chris Mason
2020-09-17 11:06         ` Ævar Arnfjörð Bjarmason
2020-09-17 14:14           ` Christoph Hellwig
2020-09-17 15:30           ` Junio C Hamano
2018-01-17 20:55 ` Jeff King
2018-01-17 21:10   ` Christoph Hellwig

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20150623232921.GB14324@thunk.org \
    --to=tytso@mit.edu \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=peff@peff.net \
    --cc=sbeller@google.com \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Git Mailing List Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/git/0 git/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 git git/ https://lore.kernel.org/git \
		git@vger.kernel.org
	public-inbox-index git

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.git


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git