[CentOS-virt] how to add file-based disk space to a guest

Wed Aug 3 13:08:36 UTC 2011
thomas veymont <thomas.veymont at gmail.com>

thanks for your answer,

sure I could use the GUI but I wanted, somehow, to understand
how to do it with the shell commands (useful in some situation).


>Trey Dockendorf treydock at gmail.com
>Tue Jul 26 19:44:06 EDT 2011
>I'm not aware of a virsh attach disk command but if you duplicate the
>entries for the existing disk you can then add the new one...something like
># virsh -c qemu:///system edit VMname
>  <disk type='file' device='disk'>
>     <driver name='qemu' type='qcow2' cache='none'/>
>     <source file='/var/lib/libvirt/images/vmname_var.qcow2'/>
>     <target dev='vda' bus='virtio'/>
>     <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
>   </disk>
>You will have to adjust the values of course.
>Why not try doing this with virt-manager?  When I started using KVM (after
>moving from ESXi) I had trouble with all the commands and finding everything
>I needed, but virt-manager works great.
>- Trey

2011/7/20 thomas veymont <thomas.veymont at gmail.com>:
> hi there,
> I'm following these documentations to add a file-based disk volume to
> a KVM guest under Centos 6.0 :
> http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization/chap-Virtualization-Storage_Volumes.html
> as instructed, I created a "pool" then a "volume", file-based, e.g :
> mkdir /mnt/raid/kvm_pool1
> virsh # pool-define-as pool1 dir - - - - "/mnt/raid/kvm_pool1"
> virsh # pool-autostart pool1
> virsh # vol-create-as pool1 volume1 20G --allocation 15G --format qcow2
> now I want to associate "volume1" to my guest OS. Following this doc:
> http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization/sect-Virtualization-Virtualized_block_devices-Adding_storage_devices_to_guests.html
> - why does this ask me to create a file with "dd" ? it's already been
> created before with the virsh pool commands, isn't it? Seems to
> me I'm bypassing the libvirt/virsh layer if I do that.
> - after that, the doc tells me to do some stuff with guest XML files.
> Is'nt there some specific commands provided by
> virsh to associate a managed Pool to a managed Guest ?
> - in this case, should I use the virsh "attach-disk" command ?
> thanks.
> --
> Tom