no /dev/st0

[philippe]

Hi All,

I try to make working mhvtl with esos. But i have a problème, because i think, no /dev/st* was created when i start mhvtl

 lsscsi -g :
[0:0:32:0]   enclosu DP       BACKPLANE        1.05  -          /dev/sg0
[0:2:0:0]    disk    DELL     PERC 6/i         1.22  /dev/sda   /dev/sg1
[0:2:1:0]    disk    DELL     PERC 6/i         1.22  /dev/sdb   /dev/sg2
[1:0:0:0]    cd/dvd  TEAC     DVD-ROM DV28EV   D.AE  /dev/sr0   /dev/sg4
[5:0:0:0]    disk    Kingston DataTraveler 2.0 PMAP  /dev/sdc   /dev/sg3
[6:0:1:0]    mediumx HP       MSL6000 Series   2.00  -          /dev/sg7
[6:0:1:1]    tape    HP       Ultrium 3-SCSI   N11G  -          /dev/sg5
[6:0:1:2]    tape    HP       Ultrium 3-SCSI   N11G  -          /dev/sg6


Perhaps the lack of st module ?


Someone could help me ?

[Marc Smith]

Hi,

I don't have a whole lot of experience with mhVTL and using tape devices (drives/changers) with SCST, but it looks like the SCSI devices (changer/drives) show up in your list above. You would then create SCST devices in the TUI (dev_changer and dev_tape). I'm not sure that the /dev/st* nodes are a requirement in this setup.

When you attempt to create the SCST devices, do you get an error?

--Marc

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[philippe]

verything is ok with SCST (i think) because i can map SCSI device (changer and drive) on my windows server. In my windows software (backupexec) i can see changer and drive, and they seems to work correctly : I can see tape, the drive can load the tape correctly, but it can 't read or write to the tape.

So, i want to test writing to the virtual tape directly from my ESOS server like this  :
 
vtlcmd 11 load H0001L3 (to load the tape H0001L3)
tar -czf /dev/sg5 /etc (to write to the tape)
But at this step i have this error : "tar: write error: Broken pipe"

But i think the correct syntax was : tar -czf /dev/st0 /etc but i have no /dev/st0.

I find lot of example of command lsscsi -g in the MHVTL forum, and in all of them i see the /dev/st0 for the drive like this (https://sites.google.com/site/linuxvtl2/) :

[2:0:2:0] mediumx ATL 1500 6.0 - /dev/sg4
[2:0:2:1] tape QUANTUM SuperDLT1 2323 /dev/st0 /dev/sg5
[2:0:2:2] tape QUANTUM SuperDLT1 2323 /dev/st1 /dev/sg6

but for me

[6:0:1:0]    mediumx HP       MSL6000 Series   2.00  -          /dev/sg7
[6:0:1:1]    tape    HP       Ultrium 3-SCSI   N11G  -          /dev/sg5
[6:0:1:2]    tape    HP       Ultrium 3-SCSI   N11G  -          /dev/sg6

For now, i don't know if my MHVTL install work correctly or not because i can't write to the virtual tape from my ESOS server

 -- Philippe

[Marc Smith]

Ah, yes, it does not appear to be set:

cat misc/linux-3.10.13.config | grep CONFIG_CHR_DEV_ST

# CONFIG_CHR_DEV_ST is not set

I'm enabling that option and committing it now... the new build with this option set should be posted in a couple of hours. Try it and let us know.

--Marc

[philippe]

Thanks Marc,

Now i can see the /dev/st0 :

lsscsi -g :

[6:0:1:0] mediumx SPECTRA PYTHON 5500 - /dev/sg7

[6:0:1:1] tape QUANTUM SDLT600 5500 /dev/st0 /dev/sg5

[6:0:1:2] tape QUANTUM SDLT600 5500 /dev/st1 /dev/sg6

and i can write to the virtual tape with the command :

tar -czf /dev/st0 /etc

but with backupexec, i have always an error. But i modify some drive parameters (pass-through SCSI) and now everything is OK

some tips to improve :

1 : /etc/rc.d/rc.mhvtl

there are no real stop function in the script. If you want stop the virtual tape you need to do for every device : vtlcmd ID exit

2 : /usr/bin/make_vtl_media call by the start function of /etc/rc.d/rc.mhvtl

the user VTL need to launch /usr/bin/mktape but he can't. To resolve this problem I do a chmod o+x but I think it's not the better way

The mktape program create the tape file in /mnt/mhvtl.

3 : no VTL group

VTL group is needed in the make_vtl_media otherwise NOGROUP is used (but it works)

4 : I don't know if you can do something for that:

I create in TUI device (drive and charger), I map device to group. When you need to change something in conf file of mhvtl (/etc/mhvtl), you need to restart virtual device (1). But when you do that, you lose device you are created in the TUI. (You need to recreate the device and map it to group)

– Philippe

[philippe]

Here new version of rc.mhvtl with a stop function.

Marc, could you include this file in a later build ?

[Marc Smith]

On Thu, Nov 28, 2013 at 5:11 PM, philippe <phild...@gmail.com> wrote:

Thanks Marc,

Now i can see the /dev/st0 :

lsscsi -g :

[6:0:1:0] mediumx SPECTRA PYTHON 5500 - /dev/sg7

[6:0:1:1] tape QUANTUM SDLT600 5500 /dev/st0 /dev/sg5

[6:0:1:2] tape QUANTUM SDLT600 5500 /dev/st1 /dev/sg6

and i can write to the virtual tape with the command :

tar -czf /dev/st0 /etc

but with backupexec, i have always an error. But i modify some drive parameters (pass-through SCSI) and now everything is OK

some tips to improve :

1 : /etc/rc.d/rc.mhvtl

there are no real stop function in the script. If you want stop the virtual tape you need to do for every device : vtlcmd ID exit

Done (thank you).

 

2 : /usr/bin/make_vtl_media call by the start function of /etc/rc.d/rc.mhvtl

the user VTL need to launch /usr/bin/mktape but he can't. To resolve this problem I do a chmod o+x but I think it's not the better way

The mktape program create the tape file in /mnt/mhvtl.

I updated the permissions for the binaries so they are now 755.

 

3 : no VTL group

VTL group is needed in the make_vtl_media otherwise NOGROUP is used (but it works)

Got the group added -- I also changed the UID of the 'vtl' user so it matches the GID of the new group (so you may need to merge your config. files by hand).

 

4 : I don't know if you can do something for that:

I create in TUI device (drive and charger), I map device to group. When you need to change something in conf file of mhvtl (/etc/mhvtl), you need to restart virtual device (1). But when you do that, you lose device you are created in the TUI. (You need to recreate the device and map it to group)

Yeah, I'm pretty sure there is not a way around this one... since mhVTL is completely removing the SCSI device, SCST also sees it as removed. If we were able to make changes in mhVTL without having to remove/add the SCSI tape changer/drives each time, then that would work. I'm not familiar enough with mhVTL to know if this is possible or not.

Thanks!

--Marc

[Marc Smith]

Thank you for your contribution; this has been committed with some minor changes.

--Marc

[Philippe]

Ok sorry for my bad english   ;-)

Do you see my change in the start function. It check if mhvtl is already running. In this case, it prevent to start it twice. If you are see it, you are right, it's not absolutely necessary  

-- Philippe

[Marc Smith]

Yeah, I left it out on purpose. The other rc scripts have minimal error checking and are very basic... I wanted to keep it uniform and consistent across all of these for now. 

If it tries to start and its already running, will it just give an error message? Or will it do something bad? If it does something bad, then I can add in a lock file check.

Let me know.

--Marc