topic Re: About Tar command in Operating System - Linux

About Tar command

peterchu — Thu, 15 Apr 2004 04:33:20 GMT

I want to use "tar" to incremental backup the file to the tape , so I will use the same tape to backup the files for a week , but I found everytime I backup the file the tape will be eject from the drive , which device is no-rewind device ( I use /dev/st0 now )? what is the tar command to append the files ? thx.

Re: About Tar command

Francisco J. Soler — Thu, 15 Apr 2004 05:21:35 GMT

Hi,
tar cvf device files -> to copy files to tape
tar xvf device -> to extract.
tar rvf device files -> to append files.

Be careful, because if you append a file that is already in the tape, the file is copied again, so when you restore your copy you must wait to the end of tape to get the latest version of that file.

Frank.

Re: About Tar command

peterchu — Thu, 15 Apr 2004 05:59:00 GMT

thx reply , I tried that -r is work fine to backup to a file but not to the tape device /dev/st0 , if use this tape device , it can only list the previous backup file can't list the appended files , could suggest what is wrong ? thx

Re: About Tar command

Francisco J. Soler — Thu, 15 Apr 2004 06:06:38 GMT

Hi,

Check the command mt, i don't know it very well but something like this could work:

mt -f device rewind
mt -f device fss
tar tvf device

Frank.

Re: About Tar command

Jeroen Peereboom — Thu, 15 Apr 2004 06:25:33 GMT

Peter,

first of all: assign some points to the 168 of 169 answers people have sent to you.
Check your forum profile and take some time to assign points. And read the forum etiquette...

About your question: do you want 1 tar file on the tape, or multiple tar files? If you append to the tar file on the tape, you only need to prevent the tape eject from happening. Who / what is ejecting the tape?

If you want multiple tar files, the tape must not be rewound, otherwise you have to position the tape each time.

Linux tar:
tar -u : appends files to the tar archive that are newer than those in the archive. So tar -uvf /mnt/backup will do it.

Or:
tar --create -- verbose -- listed-incremental --file
/dev/

will create incremental tar file (if exists, or full ( does not exist).
Or
tar cvf -g /
Check the man page for all the commands and qualifiers.Do some simple test on a small subdirectory.

JP

Re: About Tar command

peterchu — Thu, 15 Apr 2004 07:39:37 GMT

thx reply , I know why the tape will be eject , now I can't fix this problem ,
about your previous suggest , how can I prevent the tape rewind after run the tar ? thx

Re: About Tar command

peterchu — Thu, 15 Apr 2004 07:57:43 GMT

sorry , please ignore my previous message,

What I mean is
I know why the tape will be eject , now I CAN fix this problem , but there is still a question , about your previous suggest , how can I prevent the tape rewind after run the tar ? thx

Re: About Tar command

Fred Ruffet — Thu, 15 Apr 2004 08:42:03 GMT

tar will not rewind the tape. rewinding the tape will be done by :
mt -f /dev/st0 rewind

Re: About Tar command

Jeroen Peereboom — Thu, 15 Apr 2004 08:57:54 GMT

Peter

use /dev/nst0 for norewind.

Thanks for the points. ;-(

JP.

Re: About Tar command

Martin P.J. Zinser — Thu, 15 Apr 2004 11:12:06 GMT

Hello Peter,

RTFM ;-), specifically

http://www.dlt.com/storage/whitepapers/quantum/dlt/DLT%208000%20on%20Linux.pdf

which should cover your issues.

JP already covered the points, didn't he?

Greetings, Martin

Re: About Tar command

John Collier — Thu, 15 Apr 2004 11:35:00 GMT

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Re: About Tar command

John Collier — Thu, 15 Apr 2004 11:42:44 GMT

OOPS! That may not have worked out as well as I had hoped. Perhaps these forums don't support Chinese symbols??

Re: About Tar command

Stuart Browne — Thu, 15 Apr 2004 18:08:12 GMT