To change the group and permission of your changer device, add a script which sets the group and permission for your changer device.
Example for /dev/sg1:
vi /etc/udev/rules.d/55-bacula.rules
# fix the permissions of the standard devices to group "disk" (which bacula is a
member of)
KERNEL=="sg[0-9]*", BUS=="scsi", MODE="0660", GROUP="disk"
Then reboot your server.
After reboot, you see the changed group on the sg devices:
# ls -al /dev/sg*
crw-rw---- 1 root disk 21, 0 Sep 8 14:42 /dev/sg0
crw-rw---- 1 root disk 21, 1 Sep 8 14:42 /dev/sg1
crw-rw---- 1 root disk 21, 2 Sep 8 14:42 /dev/sg2
crw-rw---- 1 root disk 21, 3 Sep 8 14:42 /dev/sg3
crw-rw---- 1 root disk 21, 4 Sep 8 14:42 /dev/sg4
crw-rw---- 1 root disk 21, 5 Sep 8 14:42 /dev/sg5
crw-rw---- 1 root disk 21, 6 Sep 8 14:42 /dev/sg6
After reboot, you see the changed group on the sg devices:
# ls -al /dev/sg*
crw-rw---- 1 root disk 21, 0 Sep 8 14:42 /dev/sg0
crw-rw---- 1 root disk 21, 1 Sep 8 14:42 /dev/sg1
crw-rw---- 1 root disk 21, 2 Sep 8 14:42 /dev/sg2
crw-rw---- 1 root disk 21, 3 Sep 8 14:42 /dev/sg3
crw-rw---- 1 root disk 21, 4 Sep 8 14:42 /dev/sg4
crw-rw---- 1 root disk 21, 5 Sep 8 14:42 /dev/sg5
crw-rw---- 1 root disk 21, 6 Sep 8 14:42 /dev/sg6