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[Qemu-devel] The reversion of hot adding a storage disk to Linux guest.
From: |
Shu Ming |
Subject: |
[Qemu-devel] The reversion of hot adding a storage disk to Linux guest. |
Date: |
Thu, 12 Jan 2012 16:57:47 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 5.1; rv:8.0) Gecko/20111105 Thunderbird/8.0 |
Hi,
I am testing the hot plug of scsi disk to the KVM Linux guest with
the following command.
address@hidden 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
address@hidden 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:
address@hidden ~]#cat /proc/scsi/scsi
Attached devices:
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: QEMU Model: QEMU DVD-ROM Rev: 1.0.
Type: CD-ROM
Host: scsi2 Channel: 00 Id: 00 Lun: 00
Vendor: QEMU Model: QEMU HARDDISK Rev: 1.0.
Type: Direct-Access ANSI SCSI 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<address@hidden>
IBM China Systems and Technology Laboratory
- [Qemu-devel] The reversion of hot adding a storage disk to Linux guest.,
Shu Ming <=