Resize partitions on an encrypted disc
Recently I installed a fresh debian jessie on my laptop. I used this opportunity not just to switch to the next debian version, I also switched to 64 bit and encrypted my disc. I had no experience with encrypted disc setups so I trusted the debian installer. It offered several default partition options of which I chose to have a root partition with a separate home partition.
The trouble is now that the installer chose to use only 10GB for the root partition which I used up in the first week. So now I was tasked with resizing the partitions.
What I already knew
In the past I had used gparted for task like this one. Unfortunately, gparted does not support encryptet discs. I was very unconfident about doing this without a tool I knew but in the end it turned out to be rather simple.
If it had not been for the encryption, these are the steps I would have done in gparted (assuming that
root takes up the first 10GB of the disc and
home uses all the rest):
hometo the end of the disc
the actual situation
The disc layout was roughly like this:
- there is one physical volume
- the pysical volume containes a crypt
- the crypt contains two logical volumns,
- the logical volumes both contain an ext* file system
There were two aspects about this that I did not expect and that significantly simplify my task:
- I could completely ignore the encryption part. I only have to think about the logical volumes and the filesystems.
- logical volumes can use available space anywhere on the physical volume. So there is no need to "move"
what I had to do
- The necessary operations can not be applied to mounted volumes. So I had to boot into a live system.
- Get access to logical volmes inside of the crypt without mounting them (or unmount again)
- e2fsck /dev/mapper/localhost--vg-home
- resize2fs /dev/mapper/localhost--vg-home 200G
- will warn if specified size is smaller than actual data
- lvreduce -L -10GB /dev/mapper/localhost--vg-home
- resize2fs /dev/mapper/localhost--vg-home
- grow root
- lvextend -L +10GB /dev/mapper/localhost--vg-root
- e2fsck /dev/mapper/localhost--vg-root
- resize2fs /dev/mapper/localhost--vg-root