One of my server has only 300M space, I have to do something to free up my hard disk space.
I use VirtualBox with many Guests, so I decided shrink them.
refer to How To Shrink Your Virtualbox VM And Free Up Space For Your Hard Disk, when remount the filesystem in read-only mode, I got the following error,
mount: / is busy
after search, I got the answer, I should go to single user mode, or run the following command,
init 1
btw, Â we can also try to use CloneVDI.
Features  of version 2.02 include:
- Reads VDI,VHD,VMDK,Parallels HDD,RAW files and physical drives, writes VDI.
- A simple GUI Interface.
- A CLI interface too (for people who like that kind of thing!)
- Ability to compact (discard unused blocks from) the clone, with no need to run sdelete/zerofree first.
- Ability to enlarge the maximum size of a virtual disk, optionally enlarging the main partition too.
- User choice to either keep the old UUID or generate a new one for the clone.
- Some useful diagnostics about the source VDI, such as the partition map and the internal fileystem.
- Better feedback while cloning: a progress bar and an estimated time to completion.
- It seems to be significantly faster than “VBoxManage clonehd”.
- Open source.