/dev/st0: no such device aka. where is my tape drive

[Runar Jørgensen]

Greetings

I'm having some trouble switching tape devices.Unfortunately I
have to switch from a HP C1529 to a HP C1520F. From some other
postings on ITRC :-) I think the tape drives are as follows.

C1529: DDS-2. HP Surestore DAT8e(?).
C1520F: DDS-1. HP Surestore 2000e(?).

I was using C1529 without trouble but was forced to switch. :-( .
So I unplugged that unit, and plugged in the C1520F. Then using a tape
I know works I tried to tar out a table of the tape content.
No success (see below).I can't read or write to that tape or any
other tape anymore. And I don't think this is a DDS1 vs. DDS2 problem
or a tape problem. Here's what gives.

$ tar tvf /dev/st0
tar: /dev/st0: Cannot open: No such device
tar: Error is not recoverable: exiting now
$ mt -f /dev/st0 offl
/dev/st0: No such device
$ mt -f /dev/st0m offl
/dev/st0m: No such device
$ ls -l /dev/st0 /dev/st0m
crw-rw-rw- 1 root disk 9, 0 Mar 17 17:59 /dev/st0
crw-rw-rw- 1 root disk 9, 64 Mar 17 17:59 /dev/st0m
$ /sbin/lsmod|grep st
st 29268 0 (unused)
scsi_mod 106192 3 [st sg ide-scsi]

Some stuff from dmesg:

PCI: Enabling device 00:10.0 (0116 -> 0117)
PCI: Found IRQ 10 for device 00:10.0
PCI: Sharing IRQ 10 with 00:07.5
scsi1 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.5

aic7880: Ultra Wide Channel A, SCSI Id=7, 16/253 SCBs

Vendor: HP Model: HP35470A Rev: 1009
Type: Sequential-Access ANSI SCSI revision: 02
st: Version 20020205, bufsize 32768, wrt 30720, max init. bufs 4, s/g segs 16
Attached scsi tape st0 at scsi1, channel 0, id 3, lun 0
scsi : 1 host left.
via_audio: ignoring drain playback error -11
st: Unloaded.

OS (RH 7.2?) & packages:
$ uname -r
2.4.18-3
$ rpm -q dev mt-st
dev-3.3-4
mt-st-0.7-3

Rebooting doesn't help either. Summing up:

o The device driver exist and has appropriate permissions.
o The kernel module is loaded.
o The boot recognizes the scsi host adapter and the scsi id 3 which is
the tape drive.
o I don't know of any other changes to this OS or unit.
There shouldn't be any.

Unfortunately there is no way to switch
tape device.I'm kinda stuck here. Help?

How can I get access to the tape device again?
Any suggestions anyone?

Regards,
Runar J??rgensen

[Giorgio Milanesio_1]

Hi,
what is your server model?
Maybe you don't has installed the scsi driver for tape device.

[Runar Jørgensen]

Regarding the SCSI driver, I let kudzu figure out that one by itself.
Reading the dmesg content, I can confirm that there really is an Adaptec 2940 UW SCSI adapter in there. Is there something wrong with what's reported by dmesg? Shouldn't it be that way?

Regards,
Runar J??rgensen

[M. Jansink]

Runar,

According to your dmesg it is /dev/st0 so that looks ok.

you can try the following options:

* /dev/st0 is not a 0 byte c-device anymore.
- ls -al /dev/st0

* check the compapatability between tapes from older devices of this brand.

* The tape hasn't a tar file on it.
- dd if=/dev/st0 bs=256k count=1 of=/tmp/test

* The device is DOA
- call the vendor

Frans

[Runar Jørgensen]

Greetings
Thanks for your reply. I've taken your suggestions and answered
them below. Unfortunately, I'm still not there yet. Read on.

M. Jansink wrote:
>
> Runar,
>
> According to your dmesg it is /dev/st0 so that looks ok.
> you can try the following options:
>
> * /dev/st0 is not a 0 byte c-device anymore.
> - ls -al /dev/st0

OK! The line below looks OK to me.
$ ls -al /dev/st0
crw-rw-rw- 1 root disk 9, 0 Mar 17 17:59 /dev/st0
>
> * check the compapatability between tapes from older devices of this brand.
>

Hmmm... A little harder to do. I've tried all kind of tapes.
The problem is with both tar and mt complaining about the
device. Like this:
$ tar tvf /dev/st0
tar: /dev/st0: Cannot open: No such device
$ mt -f /dev/st0 offl
/dev/st0: No such device

> * The tape hasn't a tar file on it.
> - dd if=/dev/st0 bs=256k count=1 of=/tmp/test
>
I greated the tapes myself. and I prefer tar to cpio and dd.
Just my choosing I'm not starting a discussion here. Trying your
command resultet in:
$ dd if=/dev/st0 bs=256k count=1 of=/tmp/test
dd: opening `/dev/st0': No such device

> * The device is DOA
> - call the vendor
>

OK! So I've run around and found a fellow with a SCSI adapter,
but not on a Linux box, so drivers and stuff doesn't easily
translate. However, this was just to check whether the device was
alive at all. Right?

Plugged in the C1520F, rebooted the unit. Shoved in a tape. Ran
"mt offl", and whaddyaknow, the tape was ejected. :-) Tried with
tar to read and write to the same tape. SUCCESSS! So I'm afraid
it's not the device been DOA. Unfortunately. It's nice that this
device works on his unit, but really I want it to work on my
linux unit.

Can there something about loading/unloading modules or kernel stuff
that I've missed? How can I continue to debug this issue?

> Frans

Regards,
Runar J??rgensen

[M. Jansink]

Strange indeed. From your dmesg file you see that st0 is detected however you get an error like there is no tape in the device. The device is ok so we must think in the direction of connection to the device. You stated that st0 is still a c-device. What you can do is go to the dir /usr/src/

Look for the file devices.txt and see what the major an minor numbers for device st0 are.

Make an alias for this device something like:

mknod /dev/runar c

Try writing to this fresh made device. You can also try on of these:

/dev/nrst0
/dev/nrst01
/dev/st01

That's all I can think of.

[James_173]

Hi,

You could try these,

Unplug the C1520F,power on the server, during the boot the kudzu will find that the tape drive was removed from the system and prompt you to remove configuration,keep configuration or do nothing.Select remove configuration.After boot in the system,shutdown the server.

Plug in the C1520F,power on the server.Let kudzu to find the tape drive and do the auto config with it.

Hope it helpful.

James

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