[CentOS] Question about dd (fill a hard disks' unused space with blanks)
k_krieser at sbcglobal.net
Sun Jun 7 18:51:31 UTC 2009
On Jun 7, 2009, at 12:34 PM, Les Mikesell wrote:
> Niki Kovacs wrote:
>> I'm currently experimenting with G4U (Ghost for Unix), a small
>> application sending disk images to an FTP server.
>> The application reads the whole disk bit by bit, compresses it and
>> stores it remotely. Due to this approach, it's more or less
>> filesystem-independent. The drawback is that it sometimes results in
>> huge image files.
>> Now I'm currently following a hint which suggests to fill the disks'
>> unused space with zero bits. Here's the command for that:
>> # dd if=/dev/zero of=/0bits bs=20M
>> # rm /0bits
>> Now I gave that a shot, but after half an hour or so, I got a bit
>> impatient. Now the computer does not respond any more. Does that mean
>> he's just way too busy with dd? Or is there some mistake in the
>> As I see it, it will just be chugging on and on, no? Shouldn't
>> there be
>> a 'count=x' option somewhere?
> I'll second the recommendation for clonezilla. It knows enough about
> most filesystems (including windows ntfs) to only store the used
> and it can use network storage over nfs, smb, or sshfs if you use the
> bootable CD clonezilla-live version. If you do a lot of cloning, you
> can also use the network-booting drbl version on a server that will
> boot a client into clonezilla with the image storage directory already
> NFS-mounted. There is an rpm for Centos to install this.
The problem I had with clonezilla I had when I tried it once was I was
attempting to clone a hard drive (windows) that had some bad sectors.
Clonezilla didn't handle that well at all. Either in duplicating the
drive from one drive to another, or when I tried to back it up to a
file on another USB drive failed verify. Luckily, I had done a recent
windows backup, so I went through the recovery DVD route on the new
drive, removed programs I had previously removed from the factory
install, then restored over itself. I spent a lot of effort trying to
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