Questions[vhd](server)

This issue has been extremely frustrating for us: when transferring a large VHD (virtual hard disk) file from a Windows 7 machine over the network to a physical Windows Server 2008 machine at our datacenter, the windows file transfer fails at 4 GB consistently. We have a direct 100 mbit connection from our main office to our data center.

When the transfer fails, the error message we receive is:

There is a problem accessing \\server-name\d$ Make sure you are connected to the network and try again.

It is only VHD files larger than 4 GB that fail. If we send any other file type, it works fine. If we zip the VHD, that also works. Moreover, we can send a VHD the other direction (from the data center to the main office) no problem. It is just VHD files in that direction.

Important notes:

• All partitions are NTFS!!
• There is no firewall between workstation and server
• We have tried disabling the antivirus on the workstation (no antivirus on server)
• We have tried transferring the file from a machine not on the domain
• We have tried transferring the file from a Ubuntu machine (still fails but at around 450MB instead of 4GB)
• Wireshark capture shows 40 DUP ACKs when transfer fails
• Xcopy and Robocopy (with restart flags) both fail (same point)
• FTP transfer fails at 4,14X,XXX,XXX bytes and cannot be restarted at that point
• We tried changing the file extension (stupid, but a last resort) to something other than vhd before sending it, but it still failed
• Connection is as follows: Dell Workstation (Main Office) -> Dell PowerConnect 5448 Managed Switch (MO) -> HP Procurve 2910al-24G Layer 3 Router (MO) -> 100Mb TLS link -> HP Procurve 2910al-24G Layer 3 Router (Data center) -> Dell PowerConnect 5448 Managed Switch (DC) -> Dell Server (DC)

So basically, it is JUST vhd files > 4GB, from our main office to our datacenter that fails. This all just doesn't add up... at this point I believe it is a issue with our network hardware settings, but I don't understand what the difference is between transferring a large VHD (which fails, at 4GB) and a large video file (which works always).

I am hosting several virtual machines on a host running Hyper-V Server 2008 R2. The disks were originally provisioned on a different server (2008, not R2) about 16 months ago, and were migrated onto this server one year ago. Most guests are running Windows 7.

Recently I was comparing the VHD size to used space reported by the guest, and noticed that several machines had VHD files that were 50-100% larger than actually needed. So I decided to try compacting the VHD files to free up space on the host. I followed instructions I found on the internet, roughly as follows:

1. Run CHKDSK in the guest machine
2. Run a defrag in the guest machine (Windows built-in defrag)
3. Shut down the guest
4. Open "Edit Disk..." tool in Hyper-V Manager
5. Select the VHD of interest and choose to compact it

The first time I tried this, it worked flawlessly and reduced the size of my VHD by about 50%. But for the disks of every other guest, I get this error message:

The server encountered an error trying to edit the virtual disk.

'The system failed to compact 'C:\example.vhd'. Error Code: The requested
operation could not be completed due to a file system limitation

No guests have NTFS compression enabled. There are no snapshots of these disks. What else could be causing this error?

Edit: Bonus points for anybody who describes a solution to keep dynamic VHD sizes in check automatically.

Is it possible (how) to mount an VHD file created by Windows 7 in OS X?

I found some information about how to do this on linux. There is a fuse fs "vdfuse" which uses virtualbox libs to mount filesystems supported by virtualbox. However I was unable to compile the package on osx because nearly all headers are missing and I doubt that it would work anyway...

EDIT #2: Okay I got my hands dirty and finally compiled vdfuse (http://forums.virtualbox.org/viewtopic.php?f=26&t=33355&start=0) on osx. As a starting point I used macfuse (http://code.google.com/p/macfuse/) and looked at the example file systems.

This led me to the following build script

infile=vdfuse.c
outfile=vdfuse
incdir="your/path/to/vbox/headers"
INSTALL_DIR="/Applications/VirtualBox.app/Contents/MacOS"
CFLAGS="-pipe"

gcc -arch i386 "${infile}" \
         "${INSTALL_DIR}"/VBoxDD.dylib \
         "${INSTALL_DIR}"/VBoxDDU.dylib \
         "${INSTALL_DIR}"/VBoxVMM.dylib \
         "${INSTALL_DIR}"/VBoxRT.dylib \
         "${INSTALL_DIR}"/VBoxDD2.dylib \
         "${INSTALL_DIR}"/VBoxREM.dylib \
        -o "${outfile}" \
        -I"${incdir}" -I"/usr/local/include/fuse" \
        -Wl,-rpath,"${INSTALL_DIR}"  \
        -lfuse_ino64  \
        -Wall ${CFLAGS}

You actually don't need to compile VirtualBox on your machine, just install a recent version of VirtualBox.

So now I can partially mount vhds. The separate partitions appear as block files Partition1, Partition2, ... on my mount point. However Mac OS X does not include a loopback file system and macfuse's loopback fs does not work with block files, so we need a loopback fs to mount the blockfiles as actual partitions.

What's the best way to convert a VMWare VMDK HDD file to a HyperV VHD file?

I've been tasked with converting our environment to HyperV for evaluation purposes. We are MSDN subscribers, so the MS software for the job is probably available to me if you know it.

I have been having hit or miss success with "vmdk2vhd" - about half the time it tells me "Invalid vmdk" and as far as I know they should be fine.

In windows 7 we now have the ability to create and attach VHD files as drives. Does anyone know how we can compact the dynamic disks from within windows 7?