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Bug#416119: marked as done (installation-guide-i386: use qemu to "test" you'll reboot correctly (limited use))



Your message dated Sun, 25 Mar 2007 02:00:36 +0100
with message-id <200703250300.37186.elendil@planet.nl>
and subject line Bug#416119: installation-guide-i386: use qemu to "test" you'll reboot correctly (limited use)
has caused the attached Bug report to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

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Debian bug tracking system administrator
(administrator, Debian Bugs database)

--- Begin Message ---
Package: installation-guide-i386
Severity: wishlist

FWIW, I used qemu to test my remote install of debian will boot
correctly.  There are some outstanding issues with this line of thought.
However, for those that want to persue this, it can be a comfort to have
a high degree of confidence the system will survive the next reboot. (if
it's 100s-1000s of miles/km away, you're hosed if it dies!)

One outstanding issue is the existing drive and partition layout.  My
previous FC4 layout was like thus:

FC4:~# fdisk -l /dev/sda

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   83  Linux
/dev/sda2              14         262     2000000+  82  Swap
Partition 2 does not end on cylinder boundary.
/dev/sda3             262       19457   154183929+  83  Linux

sda1 was /boot
sda2 was swap
sda3 was /

After debootstrapping (and fdisk updating, and mkfs.ext3) /dev/sda2 is
the new /.

I used fdisk to print the layout in sectors:

Command (m for help): u
Changing display/entry units to sectors

Command (m for help): p

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/sda1              63      208844      104391   83  Linux
/dev/sda2   *      208845     4208845     2000000+  83  Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3         4208846   312576704   154183929+  83  Linux

As we see, /dev/sda2 ends at 4208845 sectors.

While /dev/sda3 is mounted (and pref sda2+sda1 are unmounted), run:
dd if=/dev/sda of=qemucheck.bin count=4208845
on the filesystem that uses /dev/sda3. If qemu supports -curses, run:
screen qemu -curses qemucheck.bin

The other outstanding issues here are:
1. qemu and dependencies will need to be installed.
2. qemu with the scsi.patch (enables -sda .. -sdg) will need to be used
to more accurately simulate for scsi systems. (still not available in
debian)
3. this assumes the user has enough knowledge of using alt+2 to switch
(-curses is only avaialable in newer releases of qemu)
to the qemu control console when needed (eg, system_reset)
4. screen helps to...
5. You have to be *lucky* or clever to adapt to partition layout issues.

While qemu supports -snapshot mode, it is NOT suggested for use on the
real disk.  I've tried it countless ways, all which equal great
frustration. (no loss of data reported for me; YMMV)

I know it's a mouthfull. :)  If you have little other choice but
to test it remotely, it's an option.

Thanks,


Scott Edwards
-- http://www.daxal.com/?debian+installation-guide



--- End Message ---
--- Begin Message ---
On Sunday 25 March 2007 01:12, supaplex wrote:
> FWIW, I used qemu to test my remote install of debian will boot
> correctly.  There are some outstanding issues with this line of
> thought. However, for those that want to persue this, it can be a
> comfort to have a high degree of confidence the system will survive the
> next reboot. (if it's 100s-1000s of miles/km away, you're hosed if it
> dies!)

Again, it's an interesting story, but I don't see what the impact on the 
installation guide is. It would probably be more useful to document such 
things in the wiki.

Closing the report.

Cheers,
FJP

--- End Message ---

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