From: Adam Dinwoodie <adam@dinwoodie.org>
To: cygwin@cygwin.com
Subject: Re: Renaming (with 'mv') very large files is SLOW
Date: Mon, 31 Jan 2022 21:36:15 +0000 [thread overview]
Message-ID: <20220131213615.l3bvoyacl3jcvls2@lucy.dinwoodie.org> (raw)
In-Reply-To: <25079.64935.73349.331715@consult.pretender>
On Mon, Jan 31, 2022 at 10:17:59AM -0500, cygwin@kosowsky.org wrote:
> Eliot Moss wrote at about 09:59:17 -0500 on Monday, January 31, 2022:
> > On 1/31/2022 9:52 AM, cygwin@kosowsky.org wrote:
> > > I tried renaming some very large files (20-40 GB) using:
> > > mv <oldname> <newname>
> > > without changing the directory of course.
> > >
> > > The process took about 10-20 minutes with Task Manager showing disk
> > > activity of 100+ MB/s.
> > >
> > > Is there something about such large 'renaming' that actually results
> > > in the file being really moved (aka copied) rather than just renamed?
> >
> > The two places are probably on different volumes (loosely, different disks).
> > That requires a physical move, even under Linux.
>
> No my point is I am just *renaming*, not physically moving the file!!
> i.e., I am not changing the directory location of the file, let alone
> the volume/disk location.
> (I am well aware that 'mv' does a copy when changing volumes/disks).
>
> I literally am typing something like:
> mv foo bar
>
> In Linux, that just edits the file system table & inode...
>
> UPDATE...
> I just tried a second 'mv' and it was near instantaneous.
> (and similarly with subsequent renaming of the same file)
> So perhaps not a 'Cygwin' thing but something going on within Windows.
>
> Could it be that the first 'mv' triggered an anti-virus read of the file since
> perhaps it detects it as a new/changed file?
>
> But if so, would 'mv' (under Task Manager) be showing the 100+ MB/s disk activity?
That definitely seems plausible; there's a reason a significant number
of the applications that are known to interfere with Cygwin operation
(see [0]) are antivirus applications. But what would trigger your
antivirus to want to scan a file, and how much work is required to do
that, is something you'll need to take up with your antivirus vendor,
I'm afraid.
[0]: https://cygwin.com/faq/faq.html#faq.using.bloda
next prev parent reply other threads:[~2022-01-31 21:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-31 14:52 cygwin
2022-01-31 14:59 ` Eliot Moss
2022-01-31 15:13 ` René Berber
2022-01-31 15:20 ` cygwin
2022-01-31 15:51 ` [EXTERNAL] " Lavrentiev, Anton (NIH/NLM/NCBI) [C]
2022-01-31 15:17 ` cygwin
2022-01-31 21:36 ` Adam Dinwoodie [this message]
2022-02-02 17:09 ` L A Walsh
2022-02-01 8:47 ` Andrey Repin
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=20220131213615.l3bvoyacl3jcvls2@lucy.dinwoodie.org \
--to=adam@dinwoodie.org \
--cc=cygwin@cygwin.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).