[libvirt-users] how to match the ID of a LUN in a storage pool with the GUID on the target server

[Tom Georgoulias]

On 06/16/2010 03:15 PM, Tom Georgoulias wrote:
> On 06/16/2010 01:41 PM, Daniel P. Berrange wrote:
>> On Wed, Jun 16, 2010 at 01:20:02PM -0400, Tom Georgoulias wrote:
>>> I've configured a libvirt storage pool using an iscsi target from a Sun
>>> 7310 storage appliance and am using the LUNs in this target as volumes
>>> for my KVM guests.  The setup is very similar to what Daniel covered in
>>> a recent blog posting:
>>>
>>> http://berrange.com/posts/2010/05/05/provisioning-kvm-virtual-machines-on-iscsi-the-hard-way-part-2-of-2/
>>>
>>> It works great, but I can't figure out how to match the volume names&
>>> path IQNs within the storage pool to the GUIDs on the target.
>>>
>>> For example, here's what I see when I use the vol-info command:
>>>
>>> # virsh vol-list kvm-target
>>> Name                 Path
>>> -----------------------------------------
>>> 6.0.0.0
>>> /dev/disk/by-path/ip-X.X.X.X:3260-iscsi-iqn.1986-03.com.sun:02:<snipped>-lun-0
>>> 6.0.0.1
>>> /dev/disk/by-path/ip-X.X.X.X:3260-iscsi-iqn.1986-03.com.sun:02:<snipped>-lun-1
>>>
>>> The IQN matches the targets IQN, but when I browse the LUNs from the
>>> storage system I do not see a way to determine which of them is *-lun-0
>>> and which is *-lun-1, I only see a GUID and an alias name that I created.
>>>
>>> Is there any way to get that info (or something else that will do the
>>> job) from a virsh command?
>>
>> Nothing at this time. If you weren't using libvirt, how would you discover
>> the GUIDs on the Linux client ? If there is a way to get these from sysfs
>> or elsewhere, we can wire it up in libvirt to the<key>   element in the XML
>> for the volume. I just don't know how yet...
>
> That's a good question, I tried to figure out a way to do so with
> iscsiadm but didn't find anything.  But I'm glad you mentioned the sysfs
> angle, it prodded me in the right direction and I think I found
> something to work with.
>
> # udevinfo -a -p $(udevinfo -q path -n /dev/sdg)
>
>
>     looking at device '/block/sdg':
>       KERNEL=="sdg"
>       SUBSYSTEM=="block"
>       SYSFS{stat}=="   20458      183   451623    17494    27820    11891
>    4508156   552205        0    70083   569695"
>       SYSFS{size}=="41943040"
>       SYSFS{removable}=="0"
>       SYSFS{range}=="16"
>       SYSFS{dev}=="8:96"
>
>     looking at parent device
> '/devices/platform/host6/session2/target6:0:0/6:0:0:0':
>       ID=="6:0:0:0"
>       BUS=="scsi"
>       DRIVER=="sd"
>       SYSFS{ioerr_cnt}=="0x3"
>       SYSFS{iodone_cnt}=="0xbcb4"
>       SYSFS{iorequest_cnt}=="0xbcb4"
>       SYSFS{iocounterbits}=="32"
>       SYSFS{timeout}=="60"
>       SYSFS{state}=="running"
>       SYSFS{rev}=="1.0 "
>       SYSFS{model}=="Sun Storage 7310"
>       SYSFS{vendor}=="SUN     "
>       SYSFS{scsi_level}=="6"
>       SYSFS{type}=="0"
>       SYSFS{queue_type}=="none"
>       SYSFS{queue_depth}=="32"
>       SYSFS{device_blocked}=="0"
>
>     looking at parent device '/devices/platform/host6/session2/target6:0:0':
>       ID=="target6:0:0"
>       BUS==""
>       DRIVER==""
>
>     looking at parent device '/devices/platform/host6/session2':
>       ID=="session2"
>       BUS==""
>       DRIVER==""
>
>     looking at parent device '/devices/platform/host6':
>       ID=="host6"
>       BUS==""
>       DRIVER==""
>
>     looking at parent device '/devices/platform':
>       ID=="platform"
>       BUS==""
>       DRIVER==""
>
> # scsi_id -g -x -s /block/sdg
> ID_VENDOR=SUN
> ID_MODEL=Sun_Storage_7310
> ID_REVISION=1.0
> ID_SERIAL=3600144f0a523738a00004c18ec990004
> ID_TYPE=disk
> ID_BUS=scsi
>
>
> The GUID for this LUN is "600144F0A523738A00004C18EC990004".  That's the
> same number that is used in the ID_SERIAL, except that it has a 3
> prepended on it.  So now I can tell which LUN is really volume 6.0.0.0.

Let me refine that.  This command does it all (if you don't mind 
checking the path for the name.  Note, I stripped the IP from my IQN).

# udevinfo -q env -p $(udevinfo -q path -n /dev/sdg)
ID_VENDOR=SUN
ID_MODEL=Sun_Storage_7310
ID_REVISION=1.0
ID_SERIAL=3600144f0a523738a00004c18ec990004
ID_TYPE=disk
ID_BUS=scsi
ID_PATH=ip-X.X.X.X:3260-iscsi-iqn.1986-03.com.sun:02:2d90ab5a-ac15-623d-a5aa-aa1baa0cfa58-lun-0