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

Cloudmin
#1

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?

#2

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?

#3

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.

#4

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?

#5

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

#6