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Re: ntfsclone for cygwin 1.7 (issues pointing to shadow copies)

On 07/28/2009 05:27 AM, Corinna Vinschen wrote:
On Jul 27 18:31, Larry Hall (Cygwin) wrote:
On 07/27/2009 05:48 PM, Rob Bosch wrote:
The issue appears to be with ntfsclone in that it must point to
something  in /proc/partitions. It will not work with any /cygdrive/X (used
dosdev.c from Corinna and typical vshadow to expose as a drive with no luck). I found
this out by commenting out the read-only check and rebuilding
ntfsclone/ntfsinfo. The code apparently uses a win32_io.c file when building
on cygwin. This file creates its own device mappings (e.g. /dev/hda1 instead
of using the existing /dev/sda1). I guess there would be a way to modify it
to use cygwin devices but I don't know how.

If shadow copies could be presented as block devices to this library
then  it would open up a lot of possibilities for creating block-level clones of
partitions without having to boot to a live CD. I guess it is dd piped
through gzip for now. It sure is a waste when you only have 50GB on a 500GB
drive since dd processes the entire drive.

Does anyone have anything else to add? I'm guessing not...

Not much in the way of specific help, no, but I can make two observations:

   1. Using win32_io.c under Cygwin is almost certainly the wrong thing,
      since you'll then be using Win32isms in an environment built to expect
      POSIX mechanisms.

   2. It looks like /proc/partitions isn't populated, so if /proc/partitions
      is the only way that ntfsclone expects to be able to find what it
      wants, then it will be disappointed until a patch is supplied to
      support this.

/proc/partitions is populated, but only with actual disks. The device mapping for disks is a mapping from the internal NT namespace objects \Device\HarddiskX\PartitionY to the POSIX-like /dev/sdXY. Since shadow copies of a disk don't match this mapping, you're out of luck. Maybe we can add a mapping in a later Cygwin release and I added it to my TODO list, but this is definitely no fodder for 1.7.1.

Ugh, my bad. I forgot that '/proc/partitions' was a file and not a directory. It is populated for me as well.

Larry Hall                    
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
216 Dalton Rd.                          (508) 893-9889 - FAX
Holliston, MA 01746


A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting annoying in email?

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