The /etc/devlink.tab file is called the default device table file. It specifies rules that devfsadm uses to create links in the /dev directory. This file 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 more information, see the devlinks(1M) man page.
For any tape drive visible to Oracle Solaris OS but not specified in the devlink file, devfsadm automatically assigns a minor node number starting from 0. These minor node numbers will conflict with any lower numbers assigned manually in /etc/devlink.tab, so be sure to assign numbers that are high enough to avoid conflicts.
This approach can easily lead to duplicate links in /dev/rmt. Any tapes discovered before entries were specified 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 command.
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 file.
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 in the following example.
# 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:
For example, if 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 would then add this line to the devlink file on every Oracle Solaris server on the SAN that uses this drive so that it always appears as minor node 40.
For more information, see Using Your Assigned Administrative Rights in Securing Users and Processes in Oracle Solaris 11.3.
If the devfsadm has previously discovered the devices, you must determine the device address by running the ls -l command on the existing link.
For more information about creating entries in the devlink.tab file, see Creating Tape Links.
This command creates new links as per the entries in the /etc/devlink.tab file in addition to automatically creating links for any unspecified devices. For more information about the devfsadm command, see the devfsadm(1M) man page.