2 a.m.
Hi,
Managing disks in the ovirt gui seems completely error prone since the GUI ordering does
not seem to be used in any practical way. The scsi ID's are not exposed via the GUI
either, so if you have 2 drives of the same size on NFS there's no way to identify
which is which without resorting to dumping the xml.
I see in the xml that the target dev is correct and matches up with the GUI's drive
order, but the scsi unit seems to be generated based on the order of last activated:
<disk type='file' device='disk' snapshot='no'>
<driver name='qemu' type='raw' cache='none'
error_policy='stop' io='threads'/>
<source
file='/rhev/data-center/mnt/10.1.32.10:_sas01/2060a19f-f26c-4dba-a559-83541a4d0c7a/images/b622cde9-ffc4-487b-8038-f7cb7fbc00a1/7240b4b2-5ab1-40ab-99bb-09c69fd835f6'/>
<backingStore/>
<target dev='sda' bus='scsi'/>
<serial>b622cde9-ffc4-487b-8038-f7cb7fbc00a1</serial>
<boot order='1'/>
<alias name='ua-b622cde9-ffc4-487b-8038-f7cb7fbc00a1'/>
<address type='drive' controller='0' bus='0'
target='0' unit='1'/>
</disk>
<disk type='file' device='disk' snapshot='no'>
<driver name='qemu' type='raw' cache='none'
error_policy='stop' io='threads'/>
<source
file='/rhev/data-center/mnt/10.1.32.10:_sas01/2060a19f-f26c-4dba-a559-83541a4d0c7a/images/86765f60-4240-44f4-b437-f22b2cc3df1a/482a363e-461a-4f37-876c-43ceb529a93a'/>
<backingStore/>
<target dev='sdb' bus='scsi'/>
<serial>86765f60-4240-44f4-b437-f22b2cc3df1a</serial>
<alias name='ua-86765f60-4240-44f4-b437-f22b2cc3df1a'/>
<address type='drive' controller='0' bus='0'
target='0' unit='0'/>
</disk>
<disk type='file' device='disk' snapshot='no'>
<driver name='qemu' type='raw' cache='none'
error_policy='stop' io='threads'/>
<source
file='/rhev/data-center/mnt/10.1.32.10:_sas01/2060a19f-f26c-4dba-a559-83541a4d0c7a/images/0b020d24-3dea-4be7-931a-9c25ccfeec48/7e3957ff-a3bf-4080-a7b6-ddad7f63a299'/>
<backingStore/>
<target dev='sdc' bus='scsi'/>
<serial>0b020d24-3dea-4be7-931a-9c25ccfeec48</serial>
<alias name='scsi0-0-0-3'/>
<address type='drive' controller='0' bus='0'
target='0' unit='3'/>
</disk>
After deactivating the other 2 disks and rebooting the machine, sda has now become unit
3:
<target dev='sda' bus='scsi'/>
<serial>b622cde9-ffc4-487b-8038-f7cb7fbc00a1</serial>
<boot order='1'/>
<alias name='ua-b622cde9-ffc4-487b-8038-f7cb7fbc00a1'/>
<address type='drive' controller='0' bus='0'
target='0' unit='3'/>
and then I shutdown, activated the extra 2 drives, booted it back up but now I'm still
on unit 3:
<disk type='file' device='disk' snapshot='no'>
<driver name='qemu' type='raw' cache='none'
error_policy='stop' io='threads'/>
<source
file='/rhev/data-center/mnt/10.1.32.10:_sas01/2060a19f-f26c-4dba-a559-83541a4d0c7a/images/b622cde9-ffc4-487b-8038-f7cb7fbc00a1/7240b4b2-5ab1-40ab-99bb-09c69fd835f6'/>
<backingStore/>
<target dev='sda' bus='scsi'/>
<serial>b622cde9-ffc4-487b-8038-f7cb7fbc00a1</serial>
<boot order='1'/>
<alias name='ua-b622cde9-ffc4-487b-8038-f7cb7fbc00a1'/>
<address type='drive' controller='0' bus='0'
target='0' unit='3'/>
</disk>
<disk type='file' device='disk' snapshot='no'>
<driver name='qemu' type='raw' cache='none'
error_policy='stop' io='threads'/>
<source
file='/rhev/data-center/mnt/10.1.32.10:_sas01/2060a19f-f26c-4dba-a559-83541a4d0c7a/images/86765f60-4240-44f4-b437-f22b2cc3df1a/482a363e-461a-4f37-876c-43ceb529a93a'/>
<backingStore/>
<target dev='sdb' bus='scsi'/>
<serial>86765f60-4240-44f4-b437-f22b2cc3df1a</serial>
<alias name='ua-86765f60-4240-44f4-b437-f22b2cc3df1a'/>
<address type='drive' controller='0' bus='0'
target='0' unit='0'/>
</disk>
<disk type='file' device='disk' snapshot='no'>
<driver name='qemu' type='raw' cache='none'
error_policy='stop' io='threads'/>
<source
file='/rhev/data-center/mnt/10.1.32.10:_sas01/2060a19f-f26c-4dba-a559-83541a4d0c7a/images/0b020d24-3dea-4be7-931a-9c25ccfeec48/7e3957ff-a3bf-4080-a7b6-ddad7f63a299'/>
<backingStore/>
<target dev='sdc' bus='scsi'/>
<serial>0b020d24-3dea-4be7-931a-9c25ccfeec48</serial>
<alias name='ua-0b020d24-3dea-4be7-931a-9c25ccfeec48'/>
<address type='drive' controller='0' bus='0'
target='0' unit='1'/>
</disk>
I managed to get things into the correct state by shutting down the VM, deactivating all
the disks, then activating them in the order I want them to show up. This sets the correct
order of unit 0 for sda, unit 1 for sdb, unit 2 for sdc.
Is there some way to make ovirt treat this in a sane way and always expose the scsi
devices in the same order as the GUI (and the "target dev" field)?
Cheers!
Nathan