Tips on using tar for tape backup
(Perpetually Under Construction)
The exabyte drive attached to node *hess* has device designation
/dev/rmt/0
The DAT drive attached to node *love* has device designation
/dev/rmt/0
The DAT drive attached to node *gilbert*
has device designation
/dev/rmt/0
In the following, we refer to the exabyte drive, but using the DAT drive is pretty much the same.
If you want to move a tape forward and *not* rewind, you must address
the exabyte device as
/dev/rmt/1n
As far as I know, our exabyte drive writes 2.2 Gb per tape.
to check the status of a tape in the drive (e.g. file number), try
mt -f /dev/rmt/1n status
--> the "n" at
end of device designator is critical!
To write a tar file on a tape that has k other tarfiles written on it, skip these k tarfiles with
mt -f /dev/rmt/1n fsf k
--> where k=# of
files on tape
OR -->
mt -f /dev/rmt/1n eom
--> Space to the end of recorded media on the tape.
tar cvf /dev/rmt/1 [directory(ies) and/or filename(s)]
--> to rewind tape after write
tar cvf /dev/rmt/1 -I files_to_tar
--> read files to archived from file files_to_tar
--> will rewind tape after write
tar cvf /dev/rmt/1n [directory(ies) and/or filename(s)]
--> to keep tape positioned for another write
mt -f /dev/rmt/1 offline
--> Rewind tape and eject from drive.
To read the kth tar file from on a tape, try
mt -f /dev/rmt/1n fsf k-1
--> where k=# of
file to access
tar xvf /dev/rmt/1 [directory(ies) and/or filename(s)]
--> will rewind tape after read
tar xvf /dev/rmt/1n [directory(ies) and/or filename(s)]
--> will keep tape positioned for another read
Optional:
tar tvf /dev/rmt/1n [directory(ies) and/or filenames]
--> will read filenames from tarfile, so that you be sure what you are reading.
mt -f /dev/rmt/1 offline
--> Rewind tape and eject from drive.
JPark group needs to keep track of backups on /home/park /home/vadim (both on dana's /export/home), /data/d4 /data/d7 /data/d8 /data/k3 /data/k4 /data/g1 /data/usr4. Contents of old tarfiles, as of 7/24/97, are kept in /home/park/Backup