Error: amtape: could not get changer info: cannot determine first slot

Error accurs when trying to run operation against the tape device:

amanda@amanda amanda]$ amtape DailySet1 update
amtape: could not get changer info: cannot determine first slot

Go to the /tmp/amanda to look at the changer debug files:

cat chg-zd-mtx.20060515123815.debug
chg-zd-mtx: debug 1 pid 5677 ruid 500 euid 500: start at Fri May 19 11:31:52 2006
11:31:52 Using config file /etc/amanda/DailySet1/changer.conf
11:31:52 Arg info:
       $# = 1
       $0 = "/usr/lib/amanda/chg-zd-mtx"
       $1 = "-info"
11:31:52 Running: mtx status
11:31:52 Exit code: 1
       Stderr:
cannot open SCSI device '/dev/sg0' - Permission denied
11:31:52 Exit (2) -> <none> cannot determine first slot
chg-zd-mtx: pid 5758 finish time Fri May 19 11:31:52 2006

User amandabackup does not have permission to access the scsi device:

-bash-3.00$ ls -al /dev/sg2
crw-rw----  1 root disk 21, 2 May 12 09:16 /dev/sg2

Make sure that the GID for amandabackup is set to "disk":

[root@localhost amanda]# id amandabackup
uid=500(amandabackup) gid=6(disk) groups=6(disk)

You can use the lusermod command to change the gid:

lusermod amandabackup -g 6