RH7.1 won't recognize /dev/sg18

I have an old server I will be migrating but first I need to get a good
backup of it. It's running ...

Red Hat Linux release 7.1 (Seawolf)
Kernel 2.4.2-2smp on a 2-processor i686

I have installed a qlogic scsi card and an HP DLT autochanger. I can
see the drive as /dev/st1 but I can't see the autochanger with mtx. Log
files tell me it should be /dev/sg18 but when I look at ls -l /dev/sg*
it stops at sg15, so when I try to access it with ...

mtx -f /dev/sg18 status

I get

mtx: cannot open SCSI device '/dev/sg18' - No such file or directory

I can provide more info if needed. Any help would be appreciated.

Manuel

On Fri, 11 Jul 2008 16:50:31 +0000, Manuel Ortiz wrote:
[color=blue]
> I have an old server I will be migrating but first I need to get a good
> backup of it. It's running ...
>
> Red Hat Linux release 7.1 (Seawolf)
> Kernel 2.4.2-2smp on a 2-processor i686
>
> I have installed a qlogic scsi card and an HP DLT autochanger. I can
> see the drive as /dev/st1 but I can't see the autochanger with mtx. Log
> files tell me it should be /dev/sg18 but when I look at ls -l /dev/sg*
> it stops at sg15, so when I try to access it with ...
>
> mtx -f /dev/sg18 status
>
> I get
>
> mtx: cannot open SCSI device '/dev/sg18' - No such file or directory
>
> I can provide more info if needed. Any help would be appreciated.
>
> Manuel[/color]

You are dealing with a bronze age kernel, chances are there is no driver
for the autochanger. If I were you I'd just do an rsync to another machine
instead of trying to hook a piece of modern equipment to that one.

You could also try installing the latest 2.4 kernel, 2.4.36, assuming that
you can build it on a system that old, I don't know if you can.

General Schvantzkopf wrote:[color=blue]
> On Fri, 11 Jul 2008 16:50:31 +0000, Manuel Ortiz wrote:
>[color=green]
>> I have an old server I will be migrating but first I need to get a good
>> backup of it. It's running ...
>>
>> Red Hat Linux release 7.1 (Seawolf)
>> Kernel 2.4.2-2smp on a 2-processor i686
>>
>> I have installed a qlogic scsi card and an HP DLT autochanger. I can
>> see the drive as /dev/st1 but I can't see the autochanger with mtx. Log
>> files tell me it should be /dev/sg18 but when I look at ls -l /dev/sg*
>> it stops at sg15, so when I try to access it with ...
>>
>> mtx -f /dev/sg18 status
>>
>> I get
>>
>> mtx: cannot open SCSI device '/dev/sg18' - No such file or directory
>>
>> I can provide more info if needed. Any help would be appreciated.
>>
>> Manuel[/color]
>
> You are dealing with a bronze age kernel, chances are there is no driver
> for the autochanger. If I were you I'd just do an rsync to another machine
> instead of trying to hook a piece of modern equipment to that one.
>
> You could also try installing the latest 2.4 kernel, 2.4.36, assuming that
> you can build it on a system that old, I don't know if you can.[/color]

mtx can handle the auto-changer. The problem is it's not creating the
generic scsi device (/dev/sg18)

On Fri, 11 Jul 2008 18:06:23 +0000, Manuel Ortiz wrote:
[color=blue]
> General Schvantzkopf wrote:[color=green]
>> On Fri, 11 Jul 2008 16:50:31 +0000, Manuel Ortiz wrote:
>>[color=darkred]
>>> I have an old server I will be migrating but first I need to get a
>>> good backup of it. It's running ...
>>>
>>> Red Hat Linux release 7.1 (Seawolf)
>>> Kernel 2.4.2-2smp on a 2-processor i686
>>>
>>> I have installed a qlogic scsi card and an HP DLT autochanger. I can
>>> see the drive as /dev/st1 but I can't see the autochanger with mtx.
>>> Log files tell me it should be /dev/sg18 but when I look at ls -l
>>> /dev/sg* it stops at sg15, so when I try to access it with ...
>>>
>>> mtx -f /dev/sg18 status
>>>
>>> I get
>>>
>>> mtx: cannot open SCSI device '/dev/sg18' - No such file or directory
>>>
>>> I can provide more info if needed. Any help would be appreciated.
>>>
>>> Manuel[/color]
>>
>> You are dealing with a bronze age kernel, chances are there is no
>> driver for the autochanger. If I were you I'd just do an rsync to
>> another machine instead of trying to hook a piece of modern equipment
>> to that one.
>>
>> You could also try installing the latest 2.4 kernel, 2.4.36, assuming
>> that you can build it on a system that old, I don't know if you can.[/color]
>
> mtx can handle the auto-changer. The problem is it's not creating the
> generic scsi device (/dev/sg18)[/color]

I doubt that anyone here is going to be able to give you any help on
something as old as RH7.1. Even people who run OSes for years switched to
some version of RHEL years ago so the chances that someone reading this
group still has a running RH7.1 system is remote.

I think that you are making your life hard by trying to get a new piece of
equipment to work on that system, if it worked right out of the box then
it would have been fine but since it didn't I'd forget about it. There are
a lot of ways that you can accomplish your backup task. The simplest is to
just use rsync to copy your files from the old system to a new system.

On Fri, 11 Jul 2008, in the Usenet newsgroup alt.os.linux.redhat, in article
<ziNdk.220273$SV4.25799@bgtnsc04-news.ops.worldnet.att.net>, Manuel Ortiz wrote:
[color=blue][color=green]
>> Manuel Ortiz wrote:[/color][/color]
[color=blue][color=green][color=darkred]
>>> backup of it. It's running ...
>>>
>>> Red Hat Linux release 7.1 (Seawolf)
>>> Kernel 2.4.2-2smp on a 2-processor i686[/color][/color][/color]

#include <std.lecture.keeping.OS.up.to.date.h>
[color=blue][color=green][color=darkred]
>>> I have installed a qlogic scsi card and an HP DLT autochanger. I can
>>> see the drive as /dev/st1 but I can't see the autochanger with mtx. Log
>>> files tell me it should be /dev/sg18 but when I look at ls -l /dev/sg*
>>> it stops at sg15, so when I try to access it with ...
>>>
>>> mtx -f /dev/sg18 status
>>>
>>> I get
>>>
>>> mtx: cannot open SCSI device '/dev/sg18' - No such file or directory[/color][/color][/color]

ls -l /dev/sg*

Two problems - most distributions don't create more than (typically) 8
devices in that series, and many use letter names rather than numbers.
[color=blue]
>mtx can handle the auto-changer. The problem is it's not creating the
>generic scsi device (/dev/sg18)[/color]

From a 2.4 kernel 'devices.txt' file:

21 char Generic SCSI access
0 = /dev/sg0 First generic SCSI device
1 = /dev/sg1 Second generic SCSI device
...

Most distributions name these /dev/sga, /dev/sgb...;
this sets an unnecessary limit of 26 SCSI devices in
the system and is counter to standard Linux
device-naming practice.

[compton ~]$ whatis MAKEDEV
MAKEDEV (8) - create devices
[compton ~]$

so it _looks_ as if you need to run './MAKEDEV sg18' while cd'd into
the /dev/ directory. I haven't tried to do this.

Old guy

Manuel Ortiz wrote:[color=blue]
> I have an old server I will be migrating but first I need to get a good
> backup of it. It's running ...
>
> Red Hat Linux release 7.1 (Seawolf)
> Kernel 2.4.2-2smp on a 2-processor i686
>
> I have installed a qlogic scsi card and an HP DLT autochanger. I can
> see the drive as /dev/st1 but I can't see the autochanger with mtx. Log
> files tell me it should be /dev/sg18 but when I look at ls -l /dev/sg*
> it stops at sg15, so when I try to access it with ...
>
> mtx -f /dev/sg18 status
>
> I get
>
> mtx: cannot open SCSI device '/dev/sg18' - No such file or directory
>
> I can provide more info if needed. Any help would be appreciated.
>
> Manuel[/color]

Got it !

mknod -m 666 /dev/sg18 c 21,18

Did the trick. Autoloader works great.

thanks
Manuel