[CentOS-virt] Best practices for LVM and virtualization
Mathieu Baudier
mbaudier at argeo.org
Wed Feb 10 11:09:32 UTC 2010
> yes, you can add / remove disks to a VM without restarting the guest.
> look at the xm block-attach / block-detach commands
My understanding is that xm is Xen specific (I'm using Qemu/KVM)
I tried with virsh:
virsh # attach-disk 6 /dev/mapper/vg_alma_fast-lv_test_virtlvm2 vdb
Disk attached successfully
virsh # dumpxml 6
<domain type='kvm' id='6'>
...
<devices>
<emulator>/usr/libexec/qemu-kvm</emulator>
...
<disk type='block' device='disk'>
<source dev='/dev/mapper/vg_alma_fast-lv_test_virtlvm'/>
<target dev='vda' bus='virtio'/>
</disk>
<disk type='block' device='disk'>
<driver name='phy'/>
<source dev='/dev/mapper/vg_alma_fast-lv_test_virtlvm2'/>
<target dev='vdb' bus='virtio'/>
</disk>
...
</devices>
</domain>
But I still cannot see the disk using fdisk: there is no /dev/vdb.
Please note that I'm testing with a minimal CentOS installation
(without even the Base group).
So maybe it lacks some required deamons (there is no ACPI deamon for exmaple).
I will try again with an install including the Base group.
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