From: cygwin@kosowsky.org
To: moss@cs.umass.edu
Cc: cygwin@kosowsky.org, cygwin@cygwin.com
Subject: Re: Renaming (with 'mv') very large files is SLOW
Date: Mon, 31 Jan 2022 10:17:59 -0500 [thread overview]
Message-ID: <25079.64935.73349.331715@consult.pretender> (raw)
In-Reply-To: <c1e4529a-d119-1662-6eeb-2d42950802c7@cs.umass.edu>
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?
next prev parent reply other threads:[~2022-01-31 15:18 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 [this message]
2022-01-31 21:36 ` Adam Dinwoodie
2022-02-02 17:09 ` L A Walsh
2022-02-01 8:47 ` Andrey Repin
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