[libvirt-users] virt-install creates a snapshot as the volume backend
Greetings All, I was running libvirt-0.9.10 on CentOS 6.3 and it was working perfectly until yesterday when I decided to update to 6.4, which upgraded libvirt-0.9.10 to libvirt-0.10.2. I have a storage pool of type volume group, upon upgrading to libvirt-0.10.2, the disk image gets created as a snapshot on the volume group not as a regular volume. Now every time I create a vm using virt-install on a vg, the lv gets created as a snapshot not a regular lv, as a result I get the following error when I run dmesg: device-mapper: snapshots: Invalidating snapshot: Unable to allocate exception. Buffer I/O error on device dm-5, logical block 128251 Buffer I/O error on device dm-5, logical block 256 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 257 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 258 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 259 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 260 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 261 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 262 lost page write due to I/O error on dm-5 Buffer I/O error on device dm-5, logical block 263 lost page write due to I/O error on dm-5 lost page write due to I/O error on dm-5 and the following on the domain's log file: block I/O error in device 'drive-virtio-disk0': Input/output error (5) # virt-install --name="ns1" --vcpus="2" --check-cpu --ram=512 --os-variant="rhel6" --network "bridge=br0" --disk "pool=vdisks,size=22,cache=writeback" --vnc --hvm --vnclisten="0.0.0.0" --cdrom="/mnt/ISOs/centos/x86_64/CentOS-6.3-x86_64-bin-DVD1.iso" --hvm # lvs | grep ns ns1.img vm_volumes swi-aos-- 4.00m [ns1.img_vorigin] 0.00 When I try to create a volume using virt-manager on the volume group, it gets created as a snapshot. But when I create a volume using virsh, it gets created correctly; virsh # vol-create-as vdisks test 23622320128 # lvs | grep test test vm_volumes -wi-a---- 22.00g If anyone came across this issue or can provide an advice, I will appreciate it so much. -- Best Regards, Ahmed Ossama
On 04/28/2013 12:55 AM, Ahmed Ossama wrote:
Greetings All,
I was running libvirt-0.9.10 on CentOS 6.3 and it was working perfectly until yesterday when I decided to update to 6.4, which upgraded libvirt-0.9.10 to libvirt-0.10.2.
I have a storage pool of type volume group, upon upgrading to libvirt-0.10.2, the disk image gets created as a snapshot on the volume group not as a regular volume.
Now every time I create a vm using virt-install on a vg, the lv gets created as a snapshot not a regular lv, as a result I get the following error when I run dmesg:
device-mapper: snapshots: Invalidating snapshot: Unable to allocate exception. Buffer I/O error on device dm-5, logical block 128251 ...
and the following on the domain's log file:
block I/O error in device 'drive-virtio-disk0': Input/output error (5)
# virt-install --name="ns1" --vcpus="2" --check-cpu --ram=512 --os-variant="rhel6" --network "bridge=br0" --disk "pool=vdisks,size=22,cache=writeback" --vnc --hvm --vnclisten="0.0.0.0" --cdrom="/mnt/ISOs/centos/x86_64/CentOS-6.3-x86_64-bin-DVD1.iso" --hvm # lvs | grep ns ns1.img vm_volumes swi-aos-- 4.00m [ns1.img_vorigin] 0.00
When I try to create a volume using virt-manager on the volume group, it gets created as a snapshot. But when I create a volume using virsh, it gets created correctly;
virsh # vol-create-as vdisks test 23622320128
# lvs | grep test test vm_volumes -wi-a---- 22.00g
If anyone came across this issue or can provide an advice, I will appreciate it so much.
-- Best Regards, Ahmed Ossama
Hello, since 0.10.2 libvirt creates sparse logical volumes when the requested allocation is less than requested capacity. Unlike sparse files, these don't grow automatically and you get an I/O error if you fill them up. [1] virt-install requests an allocation of 0, which libvirt interprets as the smallest possible value of 4MB. Unfortunately, you can't specify a different allocation value at virt-install command line, but a fix that uses the same allocation and capacity for logical volumes is committed upstream already [2] and should be fixed in next release. In virt-manager, you should be able to set the allocation to the same value manually. Jan [1] http://libvirt.org/formatstorage.html#StorageVolFirst [2] https://git.fedorahosted.org/cgit/virt-manager.git/commit/?id=590c8dbe commit 590c8dbebfddb71874de7a98e579264ebae6859f Author: Martin Kletzander <mkletzan@redhat.com> AuthorDate: 2013-04-02 13:51:28 +0200 Don't support sparse logical volumes Sparse logical volumes are supported by libvirt, but only in case the user takes care of the reallocation, which is not what virt-install and virt-manager users want. This patch defaults the logical volumes to non-sparse ones and makes sure allocation is always equal to capacity for such volumes.
Thanks Jan. I upgraded to 0.10.2 again, and specified "sparse=false" and it worked perfectly. On 04/29/2013 06:11 PM, Ján Tomko wrote:
On 04/28/2013 12:55 AM, Ahmed Ossama wrote:
Greetings All,
I was running libvirt-0.9.10 on CentOS 6.3 and it was working perfectly until yesterday when I decided to update to 6.4, which upgraded libvirt-0.9.10 to libvirt-0.10.2.
I have a storage pool of type volume group, upon upgrading to libvirt-0.10.2, the disk image gets created as a snapshot on the volume group not as a regular volume.
Now every time I create a vm using virt-install on a vg, the lv gets created as a snapshot not a regular lv, as a result I get the following error when I run dmesg:
device-mapper: snapshots: Invalidating snapshot: Unable to allocate exception. Buffer I/O error on device dm-5, logical block 128251 ... and the following on the domain's log file:
block I/O error in device 'drive-virtio-disk0': Input/output error (5)
# virt-install --name="ns1" --vcpus="2" --check-cpu --ram=512 --os-variant="rhel6" --network "bridge=br0" --disk "pool=vdisks,size=22,cache=writeback" --vnc --hvm --vnclisten="0.0.0.0" --cdrom="/mnt/ISOs/centos/x86_64/CentOS-6.3-x86_64-bin-DVD1.iso" --hvm # lvs | grep ns ns1.img vm_volumes swi-aos-- 4.00m [ns1.img_vorigin] 0.00
When I try to create a volume using virt-manager on the volume group, it gets created as a snapshot. But when I create a volume using virsh, it gets created correctly;
virsh # vol-create-as vdisks test 23622320128
# lvs | grep test test vm_volumes -wi-a---- 22.00g
If anyone came across this issue or can provide an advice, I will appreciate it so much.
-- Best Regards, Ahmed Ossama
Hello,
since 0.10.2 libvirt creates sparse logical volumes when the requested allocation is less than requested capacity. Unlike sparse files, these don't grow automatically and you get an I/O error if you fill them up. [1]
virt-install requests an allocation of 0, which libvirt interprets as the smallest possible value of 4MB. Unfortunately, you can't specify a different allocation value at virt-install command line, but a fix that uses the same allocation and capacity for logical volumes is committed upstream already [2] and should be fixed in next release.
In virt-manager, you should be able to set the allocation to the same value manually.
Jan
[1] http://libvirt.org/formatstorage.html#StorageVolFirst
[2] https://git.fedorahosted.org/cgit/virt-manager.git/commit/?id=590c8dbe commit 590c8dbebfddb71874de7a98e579264ebae6859f Author: Martin Kletzander <mkletzan@redhat.com> AuthorDate: 2013-04-02 13:51:28 +0200 Don't support sparse logical volumes
Sparse logical volumes are supported by libvirt, but only in case the user takes care of the reallocation, which is not what virt-install and virt-manager users want. This patch defaults the logical volumes to non-sparse ones and makes sure allocation is always equal to capacity for such volumes.
-- Best Regards, Ahmed Ossama
participants (2)
-
Ahmed Ossama -
Ján Tomko