yearly backups

[Rick Garland]

Hi all:

Got requests coming in from clients to perform the yearly backup. Catch is they do not want via OmniBack or some other proprietary utility. They want the backup to be performed via a backup utility that is portable to other UNIX platforms. TAR was a mention.

Questions, can TAR span multiple tapes for a complete system backup? Do I need to TAR some stuff to the tape and then TAR some additional stuff to another tape to get past the storage limit on DLTs?

Can vxdump be by other UNIX flavors in case a restore is needed?

I have an idea to use dd for the backup but will this span multiple tapes?

Are there any oponions as to the tool to use for this task?

Going through the research stage here and I need to get the info as this is a one-shot deal

[James R. Ferguson · Accepted solution]

Hi Rick:

I'd use 'tar' since its such "common-change". From the man pages, "When end-of-tape is reached, tar prompts the user for a new special file and continues.".

One other consideration is that the standard 'tar' will not handle files larger than 2GB nor will it handle user or group id`s larger than 60,000.

Regards!

...JRF...

[A. Clay Stephenson]

Hi Rick:

If it were me and portability is a concern, I would stick to the old reliable - tar. I would use the Gnu version of tar to avoid the 2GB filesize restriction. Dd by itself won't span tapes. You have to prescan the data and determine how much will fit on a tape and then pipe the output of tar or cpio through dd and prompt for a new tape when you reach capacity.
The only reason to do this is to get better blocking factors and possibly higher transfer rates. Since this is only done once a year, I would just let them run tar.

[John Palmer]

Hi Rick,

For portability tar or cpio are possibilities. vxdump is HP specific.

Suggest you use tar with a 64Kb blocksize to improve speed and tape usage - use the b (blocking factor) flag. You'll also have to supply this to tar if you restore.

Neither tar or cpio will span tapes but you can split it into several different tar runs to seperate tapes, specifying different legs in the filesystem.

dd won't span tapes either.

Also beware files > 2Gb, standard tar won't handle them.

Regards,
John

[Jim Turner]

Hi Rick,

You might also consider "pax" which is like the best of tar and cpio mixed in with some other cool options.

I don't know how portable it is, though.

Cheers,
Jim

[Paula J Frazer-Campbell]

Hi Rick

An Idea

Use tar but from a script that starts at / and finds files.

Note their size.

Add up sizes.

When total size = backup device size ie 12/70 gig.

Tar those file to device.

Request a tape change.

Do it again.

ETC
ETC

Simple with only one variable (the dat/dlt drive).

For safety do each twice.

HTH

Paula

[Helen French]

Hi Rick,

In the case of tar - Yes, it will span multiple tapes during backup. Once the media is full, it will ask you to enter the device file (/dev/rmt/0m) for the next media.

Shiju

[Paula J Frazer-Campbell]

Rick

An addition to your script could check for files greater than 2 gig, if found gzip them and retest the size, if under 2 gig continue, if over fire up error warning.

Paula

[Uday_S_Ankolekar]

Hi,
Hi,

There are many disadvantages in using dd. Like, It's not possible to restore single file or directory from backup
Not possible to restore files based on a "pattern-match"
Difficult to create backups that can be recovered on other systems and It's not possible to perform incremental backups. DD is basically a image copy.

Some of the backup commands, specifically tar, cpio, pax will support files up to 2GB
only. Attempts to archive any files >2GB would fail.

Try using GNUTAR instead ... http://hpux.asknet.de/hppd/hpux/Gnu/tar-1.13.18

Goodluck,
-USA..

[John Palmer]

Rick,

Apologies, tar will span tapes but only if you run it interactively.

I used to use it for cron'd backups and it would fail at end of tape with 'unable to access /dev/tty'.

Regards,
John

[Deshpande Prashant]

HI
For files greater than 2 GB, you may need to use the GNUtar. The normal tar/cpio will not help for fles bigger than that.

Thanks.
Prashant.

[harry d brown jr]

Rick,

Uday has it right, use GNU's tar, because it WILL span tape drives:

http://www.gnu.org/manual/tar/html_mono/tar.html#SEC131

software can be found here:
http://hpux.connect.org.uk/hppd/hpux/Gnu/tar-1.13.25/
(nov 2001)

live free or die
harry

[fg_1]

Rick

You can use GNU TAR to accomplish this, but I prefer CPIO since I believe it to be much faster than TAR.

Anyway here is a link to GNU TAR.

http://hpux.asknet.de/hppd/hpux/Gnu/tar-1.13.18

Hope this assist you in your task.

Good luck.

FG.