From: cygwin@kosowsky.org
To: "René Berber" <rene.berber@gmail.com>
Cc: cygwin@cygwin.com
Subject: Re: Renaming (with 'mv') very large files is SLOW
Date: Mon, 31 Jan 2022 10:20:08 -0500 [thread overview]
Message-ID: <25079.65064.763368.222635@consult.pretender> (raw)
In-Reply-To: <d3c5507d-4425-94d6-c985-30c7093d626b@gmail.com>
René Berber wrote at about 09:13:59 -0600 on Monday, January 31, 2022:
> On 1/31/2022 8:59 AM, Eliot Moss wrote:
>
> > 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. Your
> > volumes seem a bit slow to access - is one perhaps across a slow
> > network? The rates you cite suggest movement of 50Mb/s (50Mb read +
> > 50Mb write = 100Mb overall). For 40 Gb that should take 40Gb / 50Mb
> > = about 820 secs = a little under 14 mins.
> >
> > (When I say your volumes are slow, I speak from the luxury of having
> > a 2Tb solid state drive! Actually, those speeds may be reasonable
> > depending on the nature of your system.)
> >
> > If the two locations are on different drives, there's no real
> > avoiding this.
>
> Nope, I've also complained about this (long ago), if the two locations
> are the same remote drive... Cygwin moves the entire file over the network.
>
> I ended up writing my own Samba mv command.
> --
In my case the directory (where I renamed the file) is on my C-drive.
next prev parent reply other threads:[~2022-01-31 15:20 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 [this message]
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
2022-02-02 17:09 ` L A Walsh
2022-02-01 8:47 ` Andrey Repin
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