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Re: [Qemu-devel] disk image: self-organized format or raw file
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] disk image: self-organized format or raw file |
Date: |
Tue, 12 Aug 2014 20:21:06 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, 08/12 08:03, 吴兴博 wrote:
> I carefully read your reply and thought of it carefully. I'm sorry that
> when I said "I get it" I actually meant "I believe you" but not "I
> understand it".
> The problem would not come from cp or rsync -- It's not their fault. They
> just have no way to make it right.
> The real reason of it would be that filesystems have different allocation
> unit size.
>
> For example, a file is of 16KB in appearance, and the 4KB-12KB of it is a
> hole (0KB-4KB and 12KB-16KB has valid data).
> The FS held it has 4KB block size, so it *could* be allocated like this.
> Copying this file to a filesystem of 16KB block size would cause the entire
> 16KB filled with data, to be specific, the hole is filled with zero and
> cp/rsync have NO way to make difference.
>
> That's not a engineering issue of cp/rsync. It's a real issue cause by the
> fact that (most) filesystems have configurable block size.
>
Correct.
It's not an fault of any party, because there is no contract on this part at
all. What you suggested is not a good use case of the file system hole.
Fam
Re: [Qemu-devel] disk image: self-organized format or raw file, Kirill Batuzov, 2014/08/12
Re: [Qemu-devel] disk image: self-organized format or raw file, Eric Blake, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, 吴兴博, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, Eric Blake, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, 吴兴博, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, Eric Blake, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, Xingbo Wu, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, Fam Zheng, 2014/08/12
- Re: [Qemu-devel] disk image: self-organized format or raw file, Kevin Wolf, 2014/08/13
Re: [Qemu-devel] disk image: self-organized format or raw file, Richard W.M. Jones, 2014/08/12