linux virtIO udev problem

Below is a real life example.
2 disks are different, they have different sizes.
Fdisk detects this difference with different "disk identifier"s.
But udev gives same serial number for 2 different virtual systems at RHEV.
This is normal because VirtIO disk does not provide serial by default, this serial is logically created due to disk assigment order etc.
If serial number is important for you to write correct and unique udev rules, you must use VirtIO-SCSI.
This situation is told at this redhat article ==> https://access.redhat.com/solutions/500943
Also VirtIO-SCSI has many benefits over VirtIO ( unlimited PCI device, SCSI persistent reservation etc. )
It is preferred to use VirtIO-SCSI instead of VirtIO.

		Feel free to communicate by bulent.yucesoy@gmail.com



[server01]/#fdisk -l /dev/vdj1
Disk /dev/vdj: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x4628f0e3

   Device Boot      Start         End      Blocks   Id  System
/dev/vdj1            2048   104857599    52427776   83  Linux
[server01]/#udevadm info --query=all /dev/vdj1 | grep ID_SERIAL | cut -d "=" -f2
c50a5215-2864-4cce-b
[server01]/#

 
[server02]/#fdisk -l /dev/vdj1
Disk /dev/vdj: 107.4 GB, 107374182400 bytes, 209715200 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x8b5a1d3d

   Device Boot      Start         End      Blocks   Id  System
/dev/vdj1            2048   209715199   104856576   83  Linux
[server02]/#udevadm info --query=all /dev/vdj1 | grep ID_SERIAL | cut -d "=" -f2
c50a5215-2864-4cce-b
[server02]/#