External Tape drive installation on Red Hat Linux

[Shyna]

I have an external HP storageworks ultrium 448 tape drive that I want to install on Proliant ML 370 G5 server running red hat Linux. The tape drive has a SCSI interface and didn't come with any installation CD. How do I do this installation because its not a plug and play?
Thanks.

[Matti_Kurkela]

Most tape drives are supported by the standard Linux SCSI tape driver (module "st"). It should be automatically loaded when a SCSI tape device is detected. If necessary, you can load it manually with "modprobe st".

If you're using RHEL 5 or newer, you can use the "lsscsi" command to verify basic connectivity. It will display all the devices on the SCSI bus (also all the devices emulating a SCSI storage device, like SATA, USB and Firewire storage devices). If the "lsscsi" command is not installed, use "yum install lsscsi" or install the lsscsi RPM manually from the RedHat installation CD/DVD.

If you're using RHEL 4 or older, run "cat /proc/scsi/scsi" to verify basic SCSI connectivity.

By default, the first tape device appears as devices /dev/st0 and /dev/nst0. If you use the first device, the driver will automatically rewind to the beginning of the tape after each operation. The second device does not have this auto-rewind feature (n = no-rewind). For most advanced backup software, the second device is the proper choice.

In RedHat, the tape devices are owned by group "disk" and have permissions 660 = -rw-rw----, so only root and members of the "disk" group can use them by default. If this is not suitable to you, you must change the device permissions to suit your requirements.

You may also want to create an appropriate udev rule to make the new permissions persistent over system reboots. The default rules for tape devices look like this:

KERNEL=="st*", GROUP="disk", MODE="0660"
KERNEL=="nst*", GROUP="disk", MODE="0660"


MK

[Shyna]

Hello,

Thanks for your response. I'm not very familiar with Linux OS but the SCSI card on the server that i'm using to connect the external Tape drive has part number 403051-001. Is it not suppose to be plug & play?

[Matti_Kurkela]

I understand "plug and play" technically means you don't have to adjust any hardware settings to make the device work, and that the device contains standard-format identifiers that the operating system can use to automatically choose the correct driver for it. All PCI, PCI-X and PCI Express cards are "plug and play" in that sense: these features are included in the basic PCI bus standard.

But if the card is newer than the operating system you're using, the driver may not be included in the operating system standard drivers, or the device identifier may be unknown to the OS. In that case, you'll need a newer driver, or at the very least, a data file that tells the OS "identifier X is a device that can be used with the already-included standard driver Y".

Partsurfer.hp.com tells me the part number 403051-001 is model number 374654-B21. By searching for downloadables at http://www.hp.com/go/support you'll find this OS selection page:

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?prodNameId=437333〈=en&cc=us&taskId=135&prodTypeId=329290&prodSeriesId=437332

You must specify the exact version of your RedHat Enterprise Linux. Is it RHEL 3, RHEL 4 or RHEL 5? And is it 32- or 64-bit version?

(If you are not sure, please post the output of the following commands:

cat /etc/redhat-release
uname -a

This will allow the exact version to be identified.)

There is no driver provided for RHEL 6, probably because the required driver is already included in the RHEL 6 standard installation by RedHat. (The latest kernel upgrade packages released by RedHat for RHEL 5 might also include this driver.)

After choosing the OS on the selection page (linked above), you'll reach the download page for the appropriate driver. Since you already have an OS installed, what you need is in the "Driver - Storage Controller" category.

The other category "Software - Driver Diskettes" is for when you're installing your OS and your system disk is plugged in to this SCSI card. If I understood your situation correctly, you won't need it.

Click on the driver name to access a page that includes a longer description of the driver, and links to release notes and installation instructions.

Once the correct driver for the SCSI card is installed, the tape drive will not require an additional driver: SCSI tape drives have a very well standardized interface, so Linux's standard SCSI tape driver module "st" will detect and handle it automatically.

If you go to www.hp.com/go/support and search for downloadables with keywords "ultrium 448 external scsi", you'll find a package "Library and Tape Tools" for your OS. It is not a driver, but a collection of diagnostic and utility programs which may be useful if you have problems with your tape drive.

MK

[Shyna]

Thanks so much for you response, the server runs RHEL 3. I got another info that i have to do this echo "engage scsi" > /proc/drivers/cciss/cciss1
but unfortunately i just began learning Linux OS. So how do i do this? I have also downloaded the drivers you gave. thanks,

[Shyna]

Sorry for the error in the previous reply, the server runs REHL 4. The server was detecting the tape drive quite alright but when i tried to do the backup, it gives this error. bash: /dev/tape: No such device or address. When i tried severally to restart and free up some space on the server, it will start to backup but will terminate and give this other error message after like 30seconds. CPIO : write error: no space left on the device. Please what else can i do?

Thanks

[Steven Schweda]

> [...] The server was detecting the tape
> drive quite alright [...]

What, exactly, does that mean? As usual,
showing actual commands with their actual
output can be more helpful than vague
descriptions or interpretations.

> [...] when i tried to do the backup, it
> gives this error. bash: /dev/tape: No such
> device or address.

Why did you specify "/dev/tape"? What makes
you think that that's the right device name?

> [...] CPIO : write error: no space left on
> the device. [...]

If "/dev/tape" is not a tape device, then you
may be creating a _file_ named "/dev/tape",
and trying to store the backup data there.
This could easily fill the "/" file system.

ls -l /dev/tape

If that's a (large) plain file, then you
should probably remove it.

> [...] because its not a plug and play?

It might be "plug and play" if you knew how
to play. I know nothing, but you need to
figure out what the device name is for your
tape drive. If you didn't get any clues from
any of that stuff which you have already
done, then you might look around under "/dev"
for something new which might be your tape
drive.

Desperate?

man -k tape

[Shyna]

The only scsi device attached to server is this external tape drice and when cat /proc/scsi/scsi is used to show the scsi device currently attached, it shows ultrium2 which means its detecting the tape drive. The command for backing up is: find filename -print|cpio -ov>/dev/tape and when this is done, it gives bash: /dev/tape : No such device or address. After you restart the server once or twice, it gives this cpio: write error : No space left on device. Several tape cartridges have been used LTO1 & LTO2 but it gives the same error cpio: write error : No space left on device ).

[Steven Schweda]

> [...] when cat /proc/scsi/scsi is used to
> show the scsi device currently attached, it
> shows ultrium2 which means it[']s detecting
> the tape drive.

Here's an idea. Don't _tell_ me what
"/proc/scsi/scsi" does, _show_ me the actual
output. (Or did I already suggest that?)

> (If you are not sure, please post the output of the following commands:
>
> cat /etc/redhat-release
> uname -a
>
> This will allow the exact version to be identified.)

> Thanks so much for you response, the server runs RHEL 3.

> Sorry for the error in the previous reply, the server runs REHL 4.

This is why it is often more helpful to show
actual commands with their actual output,
instead of vague or defective descriptions or
interpretations. The new "copy+paste"
technology is a miracle in this regard.


Do you ever answer questions?

> Why did you specify "/dev/tape"? [...]

> ls -l /dev/tape

I'm still wondering.


I don't have a Red Hat system, but if I
connect a tape drive to my Debian system,
then my "/dev/tape" is a directory, and I
see actual "st" devices in "/dev":

debi# ls -lR /dev/tape
/dev/tape:
total 0
drwxr-xr-x 2 root root 80 Mar 8 22:38 by-path

/dev/tape/by-path:
total 0
lrwxrwxrwx 1 root root 10 Mar 8 22:38 pci-0000:60:01.0-scsi-0:0:4:0-nst-nst ->
../../nst0
lrwxrwxrwx 1 root root 9 Mar 8 22:38 pci-0000:60:01.0-scsi-0:0:4:0-st -> ../..
/st0


debi# ls -lRL /dev/tape
/dev/tape:
total 0
drwxr-xr-x 2 root root 80 Mar 8 22:38 by-path

/dev/tape/by-path:
total 0
crw-rw---- 1 root tape 9, 128 Mar 8 22:38 pci-0000:60:01.0-scsi-0:0:4:0-nst-nst
crw-rw---- 1 root tape 9, 0 Mar 8 22:38 pci-0000:60:01.0-scsi-0:0:4:0-st


debi# ls -l /dev/st*
crw-rw---- 1 root tape 9, 0 Mar 8 22:38 /dev/st0
crw-rw---- 1 root tape 9, 96 Mar 8 22:38 /dev/st0a
crw-rw---- 1 root tape 9, 32 Mar 8 22:38 /dev/st0l
crw-rw---- 1 root tape 9, 64 Mar 8 22:38 /dev/st0m
[...]


> man -k tape

Did you try that? Around here, it leads to
things like:

man st

which seems to contain some potentially
useful info, not the least important of which
being:

FILES
/dev/st* the auto-rewind SCSI tape devices

/dev/nst* the non-rewind SCSI tape devices


You might try:

ls -l /dev/nst* /dev/st*

Then, if you find something, you might try
using an actual tape device in your back-up
command instead of "/dev/tape" (whatever that
is).

[Steven Schweda]

> [...] you can use the "lsscsi" command [...]

That looked helpful on my Debian system
(after I installed the package).

debi# lsscsi
[2:0:4:0] tape QUANTUM DLT7000 2255 /dev/st0
[6:0:0:0] disk SEAGATE ST373453LC DX10 /dev/sda
[6:0:1:0] disk SEAGATE ST336607LC DS09 /dev/sdb
[7:0:2:0] disk SEAGATE ST336607LC DS09 /dev/sdc


There's that "/dev/st0" again.