Tape drive

JSLayton · 10-12-2005, 10:09 AM

Where does Slackware mount the tape drive by default? I have a SCSI tape drive using ID2.

cardy · 10-12-2005, 10:48 AM

Usually the first tape drive found is /dev/st0

You can check by using the dmesg

Code:

dmesg | grep -i "attached" | grep -i tape

command to see what has been detected. On my system I see this:

Code:

Attached scsi tape st0 at scsi2, channel 0, id 0, lun 0

Once you have your drive working it is worth noting that if your drive is shoeshining i.e. moving the tape back and forth a lot this is caused by the kernel only allocating a 32k tape buffer by default.

This can be changed either as a parameter to the kernel or as a parameter to modprobe when you load the st module.

Kernel Option:

in grub.conf add the following to the line starting kernel

Code:

st=128

If your using modprobe you can use the option

Code:

modprobe st buffer_kbs=128

JSLayton · 10-12-2005, 10:53 AM

OK, I did the command you gave me and it found nothing. Now, how can I fix this problem? I know it is detecting the drive on boot, but I'm guessing it's just not mounting it.

cardy · 10-12-2005, 11:16 AM

Try the command

Code:

lsmod

If you don't see the module st in the list then use the command

Code:

modprobe st buffers_kbs=128

To tell the kernel to load SCSI tape support.

JSLayton · 10-12-2005, 11:29 AM

does the modprobe command tell the kernal to load the tape on every boot or just now? After running that command, I rebooted and the tape still wasn't there....

gbonvehi · 10-12-2005, 12:39 PM

If you reboot after loading a module it would be useless since it won't load again automatically. modprobe st to load the module and see if you tape is recognized, or if you want to "feel safe" with a reboot, add the modprobe st line to /etc/rc.d/rc.modules

cardy · 10-13-2005, 04:42 AM

It would be useful to see the output from the kernel boot (you can do this using dmesg), specifically the section where your scsi card detects the tape drive. Can you post this section onto the forum (not the whole dmesg output).

stokes · 10-14-2005, 10:41 AM

Hi, sorry for interrupting but I seem to have a very similar if not the same problem. I have a tape drive installed in my Slack 10.1 box and the Adaptec card recognises the drive before Linux starts to boot.

However dmesg has revealed the following:

Code:

SCSI subsystem driver Revision: 1.00 
kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2 
kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2 
kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2

I tried "modprobe st buffers_kbs=128" and now I can see it when I do lsmod:

Code:

root@mail:~# lsmod
Module                  Size  Used by    Not tainted
st                     27832   0  (unused)

Does that mean I should be able to mount it now? I have tried this so far:

Code:

root@mail:~# mount /dev/sda1 /mnt/tape 
mount: mount point /mnt/tape does not exist 
root@mail:~# ls /mnt 
cdrom/  floppy/  hd/ 
root@mail:~# mkdir /mnt/tape 
root@mail:~# mount /dev/sda1 /mnt/tape 
mount: /dev/sda1 is not a valid block device 
root@mail:~# mount /dev/sda /mnt/tape 
mount: /dev/sda is not a valid block device 
root@mail:~# mount /dev/sdb /mnt/tape 
mount: /dev/sdb is not a valid block device 
root@mail:~# mount /dev/sg0 /mnt/tape 
mount: /dev/sg0 is not a block device

What to try next?

Hope you don't mind me hijacking this thread .. it seemed relevant and may help all of us.

cardy · 10-14-2005, 11:08 AM

Your problem is that your scsi card has not been correctly configured and the module has not loaded. Because of this the system knows nothing about the scsi devices attached to your scsi controller.

The st module has loaded correctly but because no scsi devices have been detected the module has nothing to do.

Finally tapes can not be mounted like a file system, you can use the command mt to control the tape drive once you have it correctly detected and you can read and write to the tape using programs such as tar but you can't mount it like a filesystem.

If you let me know what scsi card your using we should be able to locate the appropriate module for it.

stokes · 10-14-2005, 01:14 PM

Quote:

Originally posted by cardy
If you let me know what scsi card your using we should be able to locate the appropriate module for it.

That sounds hopeful!

The card is an Adaptec AHA-2930CU.

Thanks for your help!

stokes · 10-14-2005, 02:07 PM

I found a Linux driver and downloaded the tar.gz from here:

http://people.freebsd.org/~gibbs/linux/SRC/

I know it has freebsd in the URL but it is apparently the Linux driver. I've untarred it and installed it with "insmod aic7xxx"

Now I can see it here:

Code:

root@mail:/downloads/ben/drivers/scsi/aic7xxx# lsmod
Module                  Size  Used by    Not tainted
aic7xxx               141080   0  (unused)

I feel like I'm getting somewhere but I still cant mount it...

edit: sussed it ... it works now.

Code:

mt -f /dev/st0 status
SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 512 bytes. Density code 0x13 (DDS (61000 bpi)).
Soft error count since last status=0
General status bits on (41010000):
 BOT ONLINE IM_REP_EN

cardy: Thanks for pointing me in the right direction.

cardy · 10-24-2005, 06:29 AM

No problem, glad you got it working. What was the problem in the end ?

stokes · 10-24-2005, 06:52 AM

All I needed to do was "insmod aic7xxx"

Now I can control the tape drive using the "mt" command.

I have one final question for ya as you've resurrected this thread! I've been looking for a graphical front end for "mt" since setting this up as I'm used to using programs like Backup Exec in windows, rather than tar and gzip. I tried using KDAT which comes with KDE but it doesn't seem to be capable of mounting my tape drive. I think it's because I have to use mt to send commands to it. Any ideas?

cardy · 10-24-2005, 09:59 AM

There are a number of open source backup tools available although no GUI to mt that I know of.

I have been trialing bacula
http://www.bacula.org/ which allows you to have managed drives, there is also a free version of arkeia available which is a comercial package but will support a single tape drive and should do what you want. have a look at

http://<br /> http://www.arkeia.org...ght.html<br />

The above version is limited it depends what you wish to backup.

On a final note, you did not say what kernel your using but if you add the line

Code:

alias scsi_hostadapter aic7xxx

to the file /etc/modules.conf (if your using a 2.4 kernel) or /etc/modprobe.conf (if using a 2.6 kernel) you should find that your scsi card module will automatically be inserted.

JSLayton · 01-25-2006, 07:27 PM

Quote:

Originally Posted by cardy

Code:

modprobe st buffers_kbs=128

To tell the kernel to load SCSI tape support.

I know this is an old thread, but I just realized this. When trying to initialize this section of the code, it is telling me that buffers_kbs is not a valid parameter. Any other ideas to change the buffer size?