Serialization allows Backup Exec (tm) for Windows Servers to easily discover devices. Once a device is discovered and serialized, Backup Exec for Windows Servers records the serial number in the database and will be able to track statistics for that device, such as: cleaning, mounts, errors, and so on. If the tape device is replaced by another serialized device, Backup Exec for Windows Servers will not mix the statistic information of the new tape device when it encounters a new serial number. Serialization in single devices, although it is a benefit, does not offer the same benefits of robotic libraries.  
 

The best method for Backup Exec for Windows Servers to handle serialization with a loader/library, is if the unit supports "Element Serialization". For example, a unit that has one picker arm and four internal tape drives with a serial number associated with each element address based on a device assigned to each drive. If one of the tape drives fail and is replaced, Backup Exec for Windows Servers will be able to recognize the new tape device's serial number automatically. Element serialization will allow the new tape device's serial number to replace the old tape device serial number and record the number appropriately. In BEDIAG, a device that was detected correctly by Backup Exec for Windows Servers would be displayed as shown in (FIGURE 1).

(FIGURE 1)

Device Discovery:

SCSI Address
Prt :Bus :Tar :Lun   Attributes
-------------------  -------------------------------------------------------------------------------

0003:0000:0006:0000  Device Name             "\\.\Tape0"
                    Primary Inquiry         "SONY    SDT-9000        0400"
                    Serial Number           "SONY    SDT-9000        <1000:0003:0000:0006:0000> "
                    Device Flags            SCSI, SN(DEFAULT)
                    Device State            3, Online

                    Device IDs              1002, {DD0ED45B-126F-4999-9986-77F8923B3996}
                    Device Name             "SONY 1"
                    Device Type             16785409, "4MM 8K (32K,10,0,E)"
                    Device Features         0x00001000
                    Device Element          0, 0

Note:  The serial number for the SONY SDT-9000 is 1000:0003:0000:0006:0000.


Additionally, Backup Exec for Windows Servers handles serialization with a loader/library, if the unit supports "Device Serialization." This is where the drive elements do not have a serial number associated with the actual devices. Only the tape devices have serial numbers. On discovering the serialized devices, Backup Exec for Windows Servers will place them in the order that they are detected.  


Note: Not every unit supports element Serialization, please consult your hardware manufacturers for more information.


If there is no serialization support in the unit, then Backup Exec will search at the devices SCSI inquiry string, (the computer it is attached to: port #, bus #, ID #, logical unit number (LUN) # information) and create a serial number. If Backup Exec for Windows Servers was not able to create a serial number and properly detect the device, the BEDIAG would be as shown in Figure 2.


Figure 2

Device Discovery:

Scsi Address
Prt :Bus :Tar :Lun   Attributes
-------------------  -------------------------------------------------------------------------------

0003:0000:0006:0000  Device Name             "\\.\Tape0"
                    Primary Inquiry         "SONY    SDT-9000        0400"
                    Serial Number           ""
                    Device Flags            SCSI, SN(DEFAULT)
                    Device State            3, Online

                    Device IDs              1002, {DD0ED45B-126F-4999-9986-77F8923B3996}
                    Device Name             "SONY 1"
                    Device Type             16785409, "4MM 8K (32K,10,0,E)"
                    Device Features         0x00001000
                    Device Element          0, 0


Note: The serial number is shown as "" : this indicates that Backup Exec will not have to create a serial number for the device.