Guest images resized, OS - not. What virtualization type is the easiest to change sizes?

First time trying to resize KVM guest image. I had 30GB, now it shows 100GB. At least that’s what ‘fdisk -l’ shows:

fdisk -l

Disk /dev/vda: 107.4 GB, 107374182400 bytes
4 heads, 32 sectors/track, 1638400 cylinders
Units = cylinders of 128 * 512 = 65536 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0001c67e

Device Boot Start End Blocks Id System
/dev/vda1 17 1638400 104856576 83 Linux

Disk /dev/vdb: 3221 MB, 3221225472 bytes
4 heads, 32 sectors/track, 49152 cylinders
Units = cylinders of 128 * 512 = 65536 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0009ce93

Device Boot Start End Blocks Id System
/dev/vdb1 17 49152 3144704 82 Linux swap / Solaris

However, ‘df -h’ still shows 30GB:

df -h Filesystem Size Used Avail Use% Mounted on /dev/vda1 30G 18G 11G 64% / tmpfs 758M 0 758M 0% /dev/shm

I tried to delete and re-create partition per instructions on http://akyl.net/how-do-you-increase-kvm-guests-disk-space, starting from #6, since as I understand steps from 1 to 5 are taken care of by Cloudmin. Unfortunately, deleting and re-creating partitions change nothing, it just uses all the available number of cylinders and remain the same as before. So I tried to skip and continue from #8, however my system couldn’t fine ‘pvdisplay’ command. Too many missing points, so I am quitting to try that method. But then maybe there is another method? How exactly we should grow OS inside of resized guest image?

I guess I am having troubles because my host system is not built on LVM. Is it still possible to expand guest systems or not?

I wonder what is the easiest virtualization type to change sizes - KVM, XEN or another type? Should they necessarily be built on LVM to be resized any time or not? Could anyone elaborate on this, please?

You probably also need to resize the filesystem as well - the resize2fs command can do this.

Both Xen and KVM behave similarly when it comes to disk resizes. OpenVZ is much easier, as it doesn’t actually use disk images - just a per-VM disk limit.

Thanks for advice about resize2fs, I’ll try that later tonight.

As for OpenVZ, I’d like to give it a try if you say it is easier to manage. However, does OpenVZ allow to provide guaranteed amounts of server resources (RAM, CPU cores) to guest systems?

OpenVZ does allow you to setup a variety of resource limits, though OpenVZ is a feature only available to Cloudmin Pro… Cloudmin GPL can only make use of Xen and KVM.

-Eric