User`s guide
Creating Tape Links
The /etc/devlink.tab le is called the default device table le. It species rules that devfsadm
uses to create links in the /dev directory. Type man devlinks on the command-line interface
(CLI) for more information. This le does not contain any entries for tapes because devfsadm is
already able to create links for tape drives, but rules can be added that will modify the default
behavior for creating tape links.
For any tape drive visible to the Sun Solaris OS but not specied in the devlink le, devfsadm
automatically assigns a minor node number starting from 0. These minor node numbers will
conict with any lower numbers assigned manually in /etc/devlink.tab, so be sure to assign
numbers there that are high enough to avoid conicts.
This approach can easily lead to duplicate links in /dev/rmt. Any tapes discovered before
entries were specied in /etc/devlink.tab have automatically created links. When entries are
added and devfsadm is run, the original links remain in /dev/rmt, resulting in duplicate links.
To remove the original links in /dev/rmt, run the rm /dev/rmt/* command before running
devfsadm.
This approach cannot be used with multiple-port tape drives that are attached to multiple HBA
ports. If multiple HBA ports are attached to the same tape LUN, the system detects two tape
drives instead of one. The one that appears last in the prtconf output gets the link generated by
the /etc/devlink.tab .
The following example shows a sample entry for tape in the devlink.tab le.
type=ddi_byte:tape;addr=PWWN,LUN-number; rmt/rmt-number\M0
Change the rmt # to whatever /dev/rmt/N is required. Then change the PWWN and LUN to
match the desired tape device. You can obtain this value by running the ls -l command on the
existing /dev/rmt/ link as shown below.
# ls -l /dev/rmt/4
lrwxrwxrwx 1 root root 69 Oct 6 14:57 /dev/rmt/4 ->
../../devices/pci@1f,700000/SUNW,qlc@2/fp@0,0/st@w5005076300617717,0:
If, for example, you wanted the /dev/rmt/ number to be 40, you would create an entry in
/etc/devlink.tab like the following example:
# type=ddi_byte:tape;addr=w5005076300617717,0; rmt/40\M0
You can then add this line to the devlink le on every Solaris server on the SAN that uses this
drive so that it always appears as minor node 40.
CreatingTape Links
Solaris SAN Conguration and Multipathing Guide • April 200976