1 Frequently Asked Questions List, v 1.0.1
5 II. Finding the correct device
6 III. Operational Issues
10 Q: Where is the Makefile in the tarball?
11 A: MTX now uses GNU Autoconf to generate the Makefile. Type "./configure"
12 while in the extracted mtx directory.
14 Q: Typing 'make' gives me a bunch of errors in the Makefile. Why can't
15 you provide a Makefile that works?
16 A: Note that you need the GNU 'make'. The BSD 'make' won't work, and
17 Solaris 'make' probably won't work either. If you want a better
18 configuration and makefile system, write one, then EMAIL me the results --
19 mtx is Open Source software and needs your code contributions to grow.
21 Q: How do I compile for operating systems other than Linux?
22 A: MTX no longer needs you to edit the Makefile to compile for operating
23 systems other than Linux. Just type ./configure and go with it.
25 Q: How do I port it to OS's other than the supported ones?
26 A: Create a new scsi_ module using one of the existing modules as an
27 example (scsi_freebsd.c might be a good model). Decide what symbol
28 you want #ifdef'ed in order to include that scsi_ module. Edit
29 mtxl.c to #include your scsi_ module. Edit the Makefile to add the
30 new target, including the -D needed to #include your new scsi_ module.
32 *********************************************************************
33 Part II: Finding the correct device.
35 Q: Why does this command not work??
36 [root@Scotty mtxl-1.4.8]# ./mtx -f /dev/st0 inquiry
37 In /var/log/messages I see:
38 st0: Write not multiple of tape block size.
39 A: Note that mtx 1.2 and above use the SCSI GENERIC interface on Linux,
40 FreeBSD, and Solaris (at least). They do NOT use the tape device node.
42 Q: When I do 'mtx -f /dev/sga inquiry' it shows
43 Product Type: Tape Drive
46 But when I do a 'mtx -f /dev/sga status' it fails. Why?!
47 A: You're trying to send a robotics command to a tape drive. You need
48 to send robotics commands to robotics devices, not to tape drives. Look in
49 /proc/scsi/scsi (Linux) or camcontrol (FreeBSD) to find out what the
50 robotics device is. It will be reported as a 'Medium Changer', not a
51 'Sequential Access' or 'Tape Drive'.
53 Q: When I do 'cat /proc/scsi/scsi' it shows only one device, the tape device!
54 A: You are using a DAT autochanger that has one SCSI ID but two LUN's, LUN 0
55 and LUN 1. You need to compile a new kernel with SCAN SCSI LUNS enabled
56 or add this line to your /etc/lilo.conf (then run /sbin/lilo and reboot):
57 append="max_scsi_luns=2"
59 Q: I'm tired of typing '-f /dev/sgc' all the time. How do I set a default
60 device that 'mtx' looks at?
61 A: Set the CHANGER environment variable. For example, with 'bash':
62 export CHANGER=/dev/sgc
64 Q: I get "modprobe: can't locate module char-major-21"
65 syslog messages being squirreled away into a file on our syslog host,
66 and mtx doesn't work. What's the problem?
67 A: You need to compile SCSI generic support into your kernel (or as a module).
69 Q: When I installed mtx, a message showed
70 up on the console stating that a scsi changer was found at
71 dev sgr. However, I have no device /dev/sgr.
72 A: On Linux, do 'mknod /dev/sgr c 21 19' to create a device node. By default
73 only 16 SCSI generic nodes are created, which might not be enough if
74 you have multiple SCSI controllers with lots of devices.
76 ******************************************************
77 III. Operational issues:
79 Q: I'm using Red Hat 7.0 and mtx works fine when I type ./mtx from the
80 command line, but when I use it from scripts I get the following:
81 mtx: Request Sense: Error Code=70 (Current)
82 mtx: Request Sense: Sense Key=Aborted Command
83 mtx: Request Sense: Additional Sense Code = 4E
84 mtx: Request Sense: Additional Sense Qualifier = 00
86 A: Do "rpm -e mtx". Red Hat 7.0 includes a busted version of mtx. Your
87 script is apparently picking up the busted mtx in your path. Get rid
88 of the busted mtx, make sure that /usr/local/bin (or wherever you
89 put the "good" mtx) is in the path, and all should be well.
92 # /usr/local/bin/mtx -f /dev/sgr status
93 mtx: Request Sense: Error Code=70 (Current)
94 mtx: Request Sense: Sense Key=Not Ready
95 mtx: Request Sense: Additional Sense Code = 04
96 mtx: Request Sense: Additional Sense Qualifier = 8E
97 mtx: READ ELEMENT STATUS Command Failed
99 A: Make sure your loader is in random mode, not sequential mode.
100 Most "real" loaders (as vs. DAT autoloaders) will not properly report
101 status information unless they are in "random" mode.
104 Q: I issue 'mtx load 5' and it loads tape 5. But when I try to put the tape
105 back in the magazine, we hit problems:
106 mtx: MOVE MEDIUM from Element Address 82 to 5 Failed
108 A: Many loaders require you to first eject the tape (using 'mt' or 'tapectl')
109 before you issue an 'unload' command via 'mtx'.
111 Q: My Breece Hill loader does not properly report its slots.
112 A: Either set the "auto-inventory" feature in the loader's control panel,
113 or run 'mtx inventory' prior to running 'mtx status'.
115 Q: My Breece Hill loader takes a long time to do an inventory. mtx times
116 out and spits all over the place. Help!
117 A: Many loaders that support barcodes will perform poorly if you place tapes
118 into them without bar codes. Place bar codes on all your tapes and you
119 should be able to run 'mtx inventory' without that failure.
121 Q: How do I eject the magazine of my autoloader?
122 A: Many low-end DAT autoloaders support the removable media 'EJECT' command
123 sent to the robotics device, even though it's not documented (or required)
124 in the SCSI standards. If the loader is at /dev/sgb, simply do
125 'mtx -f /dev/sgb eject' and see what happens. (If nothing happens,
126 your autoloader doesn't support 'eject'). Some high-end libraries have
127 their own proprietary way for ejecting magazine trays, generally
128 involving abuse of the 'transfer' command and 'eepos' addendums,
129 but this is totally non-standard and undocumented.
131 Q: Is there a standard for cleaning tape bar codes?
132 A: Many libraries, and many backup programs, expect cleaning tape bar
133 codes to start with "CLN".
135 Q: How do I report a bug?
136 A: First, read this FAQ. Next, check the mtx list archives at
137 http://mtx.sourceforge.net to make sure that it's not already addressed
138 by somebody else. If your problem is still not solved, send
139 (to the mtx list) the following information:
140 Result of 'mtx inquiry' on the loader,
141 Result of 'mtx status' on the loader (minus a bunch of tapes if
142 it's a 50+ tape loader!),
143 Results of the operation that isn't working correctly.