how to use scsi tape

[mohdfarah]

Is there any any one has experince in how to use scsi drive tape:
my tape is configured well as /dev/st0.
i want to use it as backup storage but my problem that how can I :-
1-if use cpio with tape how can
a-the size of used space and the remainning space.
b-the position of the tape (the last file been saved)
2-how can rewind it
3-what is different between the /dev/st0 and /dev/nst0
4-can i use same command that used with tar.
5-what is better tar or cpio and whay.

[solarisman]

have you heard of Amanda? It's a tape backup program for Linux that comes with Fedora (I think). Do a search on this site and you should find lots of info

[gthill]

mt is a good for scsi tapes
man mt

It is good to make soft links to the devices ie
ln -s /dev/st0 /dev/dlt0 # use tape type ie. /dev/dlt0 /dev/dat0 /dev/exab0 /dev/exab1...
ln -s /dev/nst0 /dev/nrdlt0 # n stands for no rewind device
eg
mt -t /dev/dlt0 rewind
mt -t /dev/dlt0 eject
mt -t /dev/dlt0 fsf 1 # forward space one file
mt -t /dev/dlt0 retension
mt -t /dev/dlt1 weof # write end of files
you can move the tape forwards, backwards, stop at end of data, stop at beginnning of file or end of file
or stop at beginning of the 12th file
mt -t /dev/dlt0 fsf 11

lots of options
see man mt
tar is very versatile for magnetic media.

ie
cd /
tar -cvf /dev/dlt0 usr
will archive the whole path /usr
$man tar # lots of options including compression
can't comment on cpio

you can find your device info usually in /proc/scsi/scsi

[mohdfarah]

thk u, i found ur info helpful ?but i have some question ?
u said it is good to make soft links to the devices? can i know y?
-how can i know it's rewindable or not?
i found this info about my device :
[root@mail ~]# more /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: ATA Model: ST380013AS Rev: 3.43
Type: Direct-Access ANSI SCSI revision: 05

[gthill]

u said it is good to make soft links to the devices? can i know y?

As you add other tape devices it makes sense to give them meaningful names so you can relate more easily to them.
ie exabytes, dlt8000,lto ultrium 400gb
/dev/exab0 /dev/exab1 /dev/exab2...
/dev/hdc -> /media/cdrom (same concept)
/dev/lto0 /dev/lto1.. and put labels on the drives.

-how can i know it's rewindable or not?
You will need to consult your manuals or google it for more information.
I would imagine most scsi magnetic media devices are no-rewindable, although I have seen some older
exabyte drives without..

Also, I think this (Vendor: ATA Model: ST380013AS Rev: 3.43) is a sata disk and not a
tape drive (I googled it).

Tape drives should show sequential access

So you may need drivers too.