No other comments? Anyway, I think we need a way to hot unplug a
storage disk from the guest totally exactly liking to remove a disk
physically. After that unplugging, linux guest can not bring back the
disk by any command.
On 2012-1-12 16:57, Shu Ming wrote:
Hi,
I am testing the hot plug of scsi disk to the KVM Linux guest with
the following command.
[root@kvm-rhel-01 bin]# ./virsh qemu-monitor-command RHEL6.1-C
"pci_add auto storage file=/nfs/images/storage1-qcow2.img,if=scsi"
OK domian 0, bus 0, slot 7, function 0
[root@kvm-rhel-01 bin]# lspci
...
00:05.0 SCSI storage controller: Red Hat, Inc Virtio block device
00:06.0 RAM memory: Red Hat, Inc Virtio memory balloon
00:07.0 SCSI storage controller: LSI Logic / Symbios Logic 53c895a
<---new deviced added
in the KVM guest:
[root@RHEL6 ~]#cat /proc/scsi/scsi
Attached devices:
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: QEMUModel: QEMU DVD-ROMRev: 1.0.
Type:CD-ROM
Host: scsi2 Channel: 00 Id: 00 Lun: 00
Vendor: QEMUModel: QEMU HARDDISKRev: 1.0.
Type: Direct-AccessANSISCSI revision: 05
<--new scsi disk attached
The command successfully created a HBA device in the guest and also
a scsi disk was enumerated under the HBA device. My next request is
to hot detach the scsi disk from the HBA device, not necessarily
detach the HBA device. That is to emulate the swapping out of the
scsi disk from a physical machine and to release the image file in the
backend. Because the scsi disk is not PCI device, "pci_del" command
can not be used in this case. Can we have a way to send some commands
to notice the HBA device to offline the scsi disk? By that way, HBA
device can do some cleanup in their driver to fully offline the scsi
disk.
BTW: In the linux guest, we can do "echo "scsi remove-single-device 2
0 0 0" > /proc/scsi/scsi" to disable the disk. But I don't think it
is fully removed, because you can bring it back again by "echo "scsi
add-single-device 2 0 0 0" > /proc/scsi/scsi"
--
Shu Ming
IBM China Systems and Technology Laboratory
