#Virtualbox increase disk size vmdk how to
#Virtualbox increase disk size vmdk software
#Virtualbox increase disk size vmdk windows

Generate new descriptor and extent files issuing the command: In the following steps, you will only need the second one but you never know what else could happen. Backup your old description file ( sdb2.vmdk) and extent file ( sdb2-pt.vmdk).You surely want to keep the new partition structure and to propagate any changes made in the partition table to the VMDK file. Please be aware that the following steps apply to the old MBR disk structure only! This obviously rendered the old extent file and the new one incompatible. Since my previous partition table did not contain any such padding, the old sdb2-pt.vmdk file only contained the first 63 sectors long extent and thus was 1 024 bytes smaller than the new one generated by the VBoxManage internalcommands createrawvmdk -filename sdb2.vmdk -rawdisk /dev/sdb -partitions 2 command.

#Virtualbox increase disk size vmdk windows

This is a padding extent which arose in my new partition table after enlarging the Windows partition (third extent in the description table). Now to the second extent (the one with only 2 sectors in size).

Since the sector size was 512 bytes in my case (I don't know if this is a general rule), the sdb2-pt.vmdk file (based on the new disk partitioning described in the extent description above) was (63+2)*512 bytes long. using the dd command on Unix-like systems. The FLAT extent file sdb2-pt.vmdk is a raw data binary file identical to one you would obtain e.g. Notice that file sdb2-pt.vmdk consists of two extents, the first 63 sectors long and the second only 2 sectors long. The offset parameter (specified only for FLAT type extents) specifies the offset (in sectors) of the given extent within the file Filename. One extent description (a row from those above) has the following structure: Access Size in sectors Type of extent Filename (Offset)

The descriptor file ( sdb2.vmdk) contains a section annotated # Extent description which can look something like this: # Extent description Their internal structure is well defined in the specification from VMWare. VMWare Disk Format (VMDK) consists of two files - a descriptor file ( sdb2.vmdk in the original question) and an extent file ( sdb2-pt.vmdk). Some background information on the VMDK file format If you only wish to learn the recovery steps, you can skip the following theoretical part. Since the VBoxManage internalcommands createrawvmdk -filename sdb2.vmdk -rawdisk /dev/sdb -partitions 2 command produces two valid files based on the current disk structure, the only change needed was to recover the Windows boot loader from the old sdb2-pt.vmdk file which is a rather straightforward process. I have finally found the solution myself.

#Virtualbox increase disk size vmdk how to

How to update the VMDK files with the new partition size to make the enlarged Windows 8.1 installation bootable from VirtualBox again? My next attempt was replacing the new sdb2-pt.vmdk with the old one (with Windows bootloader and perhaps the old partition table) - this didn't work either. This, however, made no change, because sdb2-pt.vmdk seems to be storing the boot record (MBR in my case, currently with GRUB) and some more stuff needed for Windows to work properly. The first thing which I realized that is needed to do was enlarging the partition in the VMDK file, so I backed up the old sdb2.vmdk and sdb2-pt.vmdk files and recreated them with the same command as before. These changes made the Windows installation unusable in VirtualBox of course - it fails to boot offering some repair options.

#Virtualbox increase disk size vmdk software

Last time when installing some software in Windows (PC booted up directly into Windows), I discovered there's not enough space on the system partition (/dev/sdb2) and enlarged it by 15 GB that were left spare on the HDD. VBoxManage internalcommands createrawvmdk -filename sdb2.vmdk -rawdisk /dev/sdb -partitions 2Įverything worked just fine - Windows installation was runable from VirtualBox and even bootable normally from GRUB. I have a Windows 8.1 installation on second partition of my second HDD (/dev/sdb2 in Ubuntu) created using the command