Portable Guest ... Reverting Changes?

[Spasticon]

I'm making a move from VMWare and am very pleased by the performance. I'm really liking VirtualBox.

One thing I am experiencing a problem with though is with some portable guests. I haven't had a major problem with VMWare (my portable esata drive has 2 vm definitions with the slight network changes between the two hosts).

When I do the same on VirtualBox though it seems like the two are forked. They say they are running from the same vdi, but the changes I while on one host dissapear when I get to the other host. I repeat the changes, but then they are different when I get back to the other host.

Both hosts are running Ubuntu 9.04
The guests I am running are WinXP and Win7.

They both run fine. I get no issues with either... other than the odd "snapshotting" even though I'm not actually snapshotting.

What is going on?

[vbox4me2]

You must be using 2 VDI's without you knowing it, search both Hosts for VM images and check the xml files where VBox thinks the VDI's are located.

[Spasticon]

I thought the same thing before I posted. I had double and triplechecked on both systems and they both reference the same file on the esata portable drive.

After more research though I have discovered that they are both creating difference drives on the local linux .VirtualBox folder. These definitely differ (as the name would imply) and they are not being saved to or transported on the esata portable drive.

How would I disable this behavior? I'm not creating snapshots myself, so the system is doing it for me.

My current line of research is into writethrough drives, although I'm not sure those will solve the problem.

[Spasticon]

Yea I'm just getting more confused. How do I create a writethrough drive?

VBoxManage createhd -filename TKWin7_HD.vdi -size 102400 -type writethrough

Code: Select all

VirtualBox Command Line Management Interface Version 2.2.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
Disk image created. UUID: 576c45cb-afd8-45f8-8e2f-eacdc83b31e7

Then:

VBoxManage showhdinfo TKWin7_HD.vdi

Code: Select all

VirtualBox Command Line Management Interface Version 2.2.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

UUID:                 576c45cb-afd8-45f8-8e2f-eacdc83b31e7
Accessible:           yes
Logical size:         102400 MBytes
Current size on disk: 0 MBytes
Type:                 normal (base)
Storage format:       VDI
Location:             /home/spasticon/.VirtualBox/HardDisks/TKWin7_HD.vdi

So the drive is not writethrough? It says type normal (base).

I try to change an existing VDI instead. One that was created using the Virtual Media Manager.

VBoxManage modifyhd TKWin7_HD_WritethroughTest.vdi -type writethrough

Code: Select all

VirtualBox Command Line Management Interface Version 2.2.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

ERROR: Could not find a hard disk with location 'TKWin7_HD_WritethroughTest.vdi' in the media registry ('/home/spasticon/.VirtualBox/VirtualBox.xml')
Details: code VBOX_E_OBJECT_NOT_FOUND (0x80bb0001), component VirtualBox, interface IVirtualBox, callee nsISupports
Context: "FindHardDisk(Bstr(FilenameOrUuid), hardDisk.asOutParam())" at line 415 of file VBoxManageDisk.cpp

Ok... let's check the showhdinfo?

VBoxManage showhdinfo TKWin7_HD_WritethroughTest.vdi

Code: Select all

VirtualBox Command Line Management Interface Version 2.2.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

UUID:                 4d355559-c4ff-4f5b-84ca-1a9f42c28b09
Accessible:           yes
Logical size:         102400 MBytes
Current size on disk: 0 MBytes
Type:                 normal (base)
Storage format:       VDI
Location:             /media/eSATA.320GB/VMs/TKWin7/TKWin7_HD_WritethroughTest.vdi

So I pop open VirtualBox.xml... and there it is.

Code: Select all

<HardDisk uuid="{4d355559-c4ff-4f5b-84ca-1a9f42c28b09}" location="/media/eSATA.320GB/VMs/TKWin7/TKWin7_HD_WritethroughTest.vdi" format="VDI" type="Normal"/>

What am I doing wrong?

[Spasticon]

Finally got it registered. After further research I used this command:

VBoxManage openmedium disk TKWin7_HD_WritethroughTest.vdi -type writethrough

Code: Select all

VirtualBox Command Line Management Interface Version 2.2.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

Now it shows up in Virtual Media Manager and in VirtualBox.xml as type writethrough:

Code: Select all

<HardDisk uuid="{4d355559-c4ff-4f5b-84ca-1a9f42c28b09}" location="/media/eSATA.320GB/VMs/TKWin7/TKWin7_HD_WritethroughTest.vdi" format="VDI" type="Writethrough"/>

So now my question is... if I do this on both systems and get the disk registered as writethrough in each install of VirtualBox... will it continue to create difference disks? I'll find out I suppose.