Tape Library configuration in RedHat EL AS 3.0

[Abdul Salam H S_1]

Hi,

We have a HP MSL5026S2 tape library attached to a Linux server running RH EL AS 3.0.The dmesg output shows both devices /dev/st0 (For the Tape Drive) & /dev/sge ( For the medium changer device)
So, both the robotic arm and the drive is detected by the RedHat OS.

But still we are not able to control the robotics arm using "mtx" utility which
we had downloaded. Using "mtx" we should be able to move tape from one Slot to
a Drive and from one slot to another slot.
When we executed: #mtx -f /dev/ status, the command fails.

Additionally,we have installed the HP Backup S/W "HP Data Protector" with the Cell Manager on a Windows 2000 server and Disk & Media Agents on our Linux machine.Data Protector S/W when run from the Windows machine is able to detect both the Medium Changer device & the Tape Device on the Tape Library attached to the RedHat Linux server and we are
able to successfully configure the Library.But the library is not responding to any of commands sent to the "medium changer" from the Data Protector S/W running on Windows server.

The error messages from the Software are listed below:

Cannot load exchanger medium (No additional sense information)
Description:
The exchanger failed to complete the SCSI move command . An Operating System
error or a SCIS error has been encountered. The error message indicates the
reason as reported by the Operating System or the exchanger robotics.

Does anyone have some tool similar to "mtx" or some latest version of "mtx" which
can help us in isolating the Linux side? Once we are able to control the
robotic arm from within Linux, we can check it from Data Protector side.
Awaiting for some valuable suggestions.

Thanks & Best Regards,
Abdul Salam

[xyko_1]

Hi Abdul,

did you have already solved your problem ?

If not,

did you set the CHANGER variable before trying MTX ? The command is

export CHANGER=/dev/sgX

where X is the sgid of your library. Are you fully sure that sge is you media changer ?
If you are not sure please attach the ouput of dmesg and I will try to help you.

Regards,
Xyko

[abdul salam]

Hi,

This problem was sorted out many months back. It is now successfully working with Data Protector media agent running on RedHat & we are able to backup any servers on the network.There was some issue with the Library Hardware configuration itself.Some minor setting changes were required.We verified that OS was not the issue, by loading Windows 2003 server on the system attached to the Library.Still the same problem as above was observed. Initially, we had some troubles in making the MSL library sense properly by the RedHat Linux.(It was not showing the medium changer (robotic arm) device under Linux.We had to enable scsi multi-lun support in RedHat)

Best Regards,
Abdul Salam

[xyko_1]

Hi Abdul,

good for you that your problem is solved.

I'm facing a similar problem, maybe you can help me.
I have a RedHat AS 2.1 server attached to a SAN (fibre channel) and a MSL 6060 attached to the same SAN. I can see all library using mtx status/inquiry, I can also load tapes using mtx but I can't read and write because RedHat can't see the sequential-access devices, it only sees the router (NS1200) and the media changer. All scsi modules are loaded and I can use an Adaptec attached DDS tape unit that exists on the same system.
I think that the library (or the bridge) is not able to announce itself to the operating system.
Would you please send me the library configurations settings that you have done ?

Thanks in advance.
Xyko

[abdul salam]

Hi Xyko,

Have you enabled scsi multi-lun support for Linux? The command is given below:

#echo scsi add-single-device lun> > /proc/scsi/scsi

To make it consistent across reboots, you might want to put it in the start-up rc scripts.

What does cat /proc/scsi/scsi shows? Is it showing Tape drive, NSR & the medium changer devices?

Best regards,
Abdul Salam

[xyko_1]

Hi Abdul,

first of all, thanks for you help.

I'm not sure I'm able to correctly identify all parameters I have to pass to the command you sugest, because the tape-drives are not identified. I'm attaching a file with the output of lsmod, cat /proc/scsi/scsi and dmesg. It's possible to you to show me the right parameters ?

Again, thanks.
Xyko

[Abdul Salam H S_1]

Hello,

The below is the command. Once it is executed with the proper parameters, your Drive too will be detected.
#echo scsi add-single-device lun> > /proc/scsi/scsi

You need to find out the parameters scsi-instance number, scsi channel, scsi ID & the scsi LUN number for the Tape Drive device. This can be found out if you access the NSR using a browser.As both the Library device & the medium changer device are already detected in RedHat, you have to add for the Drive only. Only after adding the entry corresponding to the drive, it will show in #cat /proc/scsi/scsi

On the NSR, can you do/verify the following
1. change the SCSI IDs from the MSL
Robotics ID1
Drive ID2
2. set the FC Port 0 discovery to "Auto discovery on reboot"
3. create a "Port 0 device map" and map the devices as follow:
0 AF Lun= 0 CTLR UP HP NS E1200-160
1 PSCSI 0 Target= 1 Lun= 0 CHGR UP COMPAQ MSL5000 Series 0423
2 PSCSI 0 Target= 2 Lun= 0 TAPE UP COMPAQ SDLT320 4B4B
4. map all hosts to this map
5 delete all entries in the "indexed" map and set the FC port map to "indexed".
6. set the FC port mode to "N_port"
7. you should zone a backupzone for each server containing only the MSL and the server
8. FW upgrdate at the NSR to 5.3.0b


Best Regards,
Abdul Salam

[xyko_1]

Hi Abdul,

Thanks for you help.
I'll try to do all the steps you told me and give you feddback.

Regards,
Xyko