Persistent Naming Support

Edit online

The device special file names are created by the IBMtape driver in the order that the tape devices are presented by the Solaris system. Each device special file name is maintained with the same logical name across reboots, even when an existing device is powered off or not connected.

However, the logical names of devices can be changed because of the swapping of connecting cables, HBA mapping changes, tape device driver updates, or other reasons.

The user can rename the logical name by editing the /etc/devlink.tab system file for the persistent name binding and reloading the IBMtape driver as follows.

Before the persistent name binding, make sure that the IBM® tape devices are configured at the different target and LUN addresses if the devices are attached on more than one HBA.

The Ultrium 3 tape drive is connected to two Emulex HBAs with the same address of target 3 and LUN 0 through a switch in the following example. You must use the HBA utility, follow HBA vendor instructions, or both to persistently bind the tape devices at the different mapped target and LUN.

# tapelist -l
Inst#  Special File     Device      Serial No     TGT/LUN    Device Physical Path   
------ -------------- ------------- ------------  --------  ------------------------------------- 
454   /dev/rmt/2st    ULT3580-TD3   1210003557    3/0       /devices/pci@6,2000/pci@1/fibre-channel@5/IBMtape@3,0  
582   /dev/rmt/8st    ULT3580-TD3   1210003557    3/0      /devices/pci@1f,2000/pci@1/fibre-channel@5/IBMtape@3,0

The tape drive is mapped at target 3, LUN 0 on HBA 1 and target 24, LUN 0 on HBA 2 after device persistent binding.

 # tapelist -l
Inst#  Special File     Device      Serial No     TGT/LUN    Device Physical Path   
------ --------------- -----------  ---------   ----------   ----------------------------------------
454   /dev/rmt/4st    ULT3580-TD3   1210003557     3/0       /devices/pci@6,2000/pci@1/fibre-channel@5/IBMtape@3,0  
1136 /dev/rmt/7st     ULT3580-TD3   1210003557    24/0       /devices/pci@1f,2000/pci@1/fibre-channel@5/IBMtape@18,0

Note: Device persistent binding is not provided on Oracle HBAs, so this persistent name approach cannot be used with the same physical drive that is attached to multiple Oracle HBA ports.

Start persistent name binding. In this example, the user renames 4st and 7st to 10st and 11st.

Create the entry for persistent naming. Determine the target address from the Device Physical Path in the output of tapelist -l and add the planned device special file name in the entry. Here, 4st and 7st drives are at 3,0 (target 3, LUN 0) and 18,0 (target 24 (0x18), LUN 0) at the device physical paths of /devices/pci@6,2000/pci@1/fibre-channel@5/IBMtape@3,0 and /devices/pci@1f,2000/pci@1/fibre-channel@5/IBMtape@18,0. Add the address and device file name into the entries:
```
type=ddi_byte:tape;addr=3,0;    rmt/10\M0
type=ddi_byte:tape;addr=18,0;  rmt/11\M0
```
Note:
1. A tab is entered between addr=3,0; and rmt/10\M0.
2. The 0 in the entry is the zero in M0.
3. To avoid conflicts with the current device special files assigned by the system automatically, be sure to assign a higher number for the persistent name.
4. The address is w500507630059f007,0 for the tape drive on the Oracle HBA with the path of /devices/pci@1,0/pci1022,7450@1/pci1077,141@1/fp@0,0/tape@w500507630059f007,0.
.
Add the entry into the /etc/devlink.tab system file.
Remove existing links that are created by the IBMtape driver from /dev/rmt by running the # rm command.
Run the # devfsadm command without any options to enable IBMtape to create the new device special file name as defined in the entries in /etc/devlink.tab. A system reboot is also required if the tape device is attached on Oracle HBA.

Run tapelist to list the device special files.

# tapelist -l
Inst#  Special File     Device      Serial No     TGT/LUN    Device Physical Path   
------ ------------- ------------ ------------- ----------  -------------------------
454   /dev/rmt/10st  ULT3580-TD3   1210003557     3/0      /devices/pci@6,2000/pci@1/fibre-channel@5/IBMtape@3,0  
1136 /dev/rmt/11st   ULT3580-TD3   1210003557    24/0      /devices/pci@1f,2000/pci@1/fibre-channel@5/IBMtape@18,0