3.0.0beta2: ->raw partitions... problems....

Postings relating to old VirtualBox pre-releases

3.0.0beta2: ->raw partitions... problems....

Postby klaus_ph » 26. Jun 2009, 17:17

beta2 of3.0.0 seems to run well.
I'm a fan on accessing on pysical hard disks (just only a partition). it means (for me) speedful access directly onto harddisk.
[was very well installed on SLES10 with vb2.x.x; but times are changing; just now SLES11 with beta2 3.0.0 ;-) ]

following doesn't work. could somebody help?
thanks a lot. [actual pdf is fully printed ;-) ]

    /dev/sda ?101.70 GB? ?IBM-SERVERAID? ? ? ? ?
    /dev/sda1? 2.01 GB? ?Linux swap ?Swap ? ?swap ?Kernel ?
    /dev/sda2? 31.00 GB? ?Linux native ?Ext3 ? ?/ ?Kernel ?
    /dev/sda3? 33.68 GB? ?HPFS/NTFS ? ? ? ? ?
    /dev/sda4? 35.01 GB? ?HPFS/NTFS ? ? ? ?
[/dev/sda3 and /dev/sda4 are prepared for vbox. they are not mounted. (certain? I think so)

my steps:
xseries346:~ # VBoxManage internalcommands createrawvmdk -filename /mnt/vb/wxp.vmdk -rawdisk /dev/sda -partitions 3 -relative -register
xseries346:~ # RAW host disk access VMDK file /mnt/vb/wxp.vmdk created successfully.

xseries346:~ # VBoxManage modifyhd /mnt/vb/wxp.vmdk settype writethrough

in /mnt/vb are two files and /wxp-ken :
wxp-pt.vmdk (it's not readable)
wxp.vmdk with content:
[list]# Disk DescriptorFile
# Extent description
RW 63 FLAT "wxp-pt.vmdk"
RW 4208967 ZERO
RW 65015055 ZERO
RW 70637805 FLAT "/dev/sda3"
RW 73417050 ZERO
RW 10020 ZERO
# The disk Data Base
ddb.virtualHWVersion = "4"

xseries346:~ # VBoxManage internalcommands listpartitions -rawdisk /dev/sda tells us:
    Number Type StartCHS EndCHS Size (MiB) Start (Sect)
    1 0x82 0 /1 /1 261 /254/63 2055 63
    2 0x83 262 /0 /1 1023/254/63 31745 4209030
    3 0x07 1023/254/63 1023/254/63 34491 69224085
    4 0x07 1023/254/63 1023/254/63 35848 139861890

BUT in graphical "Sun VirtualBox" we'll see:
wxp.vmdk with size 100GB /this is !whole! /dev/sda
at this point I have stopped.

what hat happens? what have I done wrong?

thanks a lot
Yours Klaus

NB :
bytheway: I don't want to use fileimages or other bullsh*t ;-) ; I want to use raw hard disk access.
basicly born on os/2, later ecs2. matureness on linux, loving real servers from ibm ;-)
bytheway: I HATE deleting of msg, unequal if mine or not. in german forums (qnap/os2_org) this happens. I wish, this would be NOT happen in virtualbox_forum!
Posts: 29
Joined: 9. May 2008, 00:44

Re: 3.0.0beta2: ->raw partitions... problems....

Postby aeichner » 26. Jun 2009, 22:39

This is absolutely normal. As you can see in the generated VMDK only sda3 is accessed. The problem is that we cannot change the hard disk size the OS will see because they don't like it if the hard disk layout changes. Especially Windows is very picky about changes and refuses to boot.
The guest does not have access to the other partitions on the host disk only to the MBR with the partition table which was copied into a separate file (The first line below #Extent description) so that it can't change the one on the real disk. Every other partition except the one you specified is marked as ZERO. This means that the guest will only read zeros from these parts of the virtual disk and writes wont have any effect.
Oracle Corporation
Posts: 172
Joined: 31. Aug 2007, 19:12

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