News Group Posts

supertar backup features compatability not

proprietary

From: bv@wjv.comREMOVE (Bill Vermillion)
Subject: Re: longtime recovery wtih supertars (was: Re: How can i see whats on a backup tape?
References: <WV4B9.13042$TK2.1214776@juliett.dax.net>
<3DD4F007.9000902@pcunix.com>
<8$w82niVhFB@zocki.toppoint.de> 
Date: Sat, 16 Nov 2002 06:58:15 GMT

In article <8$w82niVhFB@zocki.toppoint.de>,
Rainer Zocholl <UseNet-Posting-02141-@zocki.toppoint.de> wrote:
> (Tony Lawrence)  15.11.02 in /comp/unix/sco/misc:
>

>>FAR better solution: http://aplawrence.com/Reviews/supertars.html

>I agree your recommandation to supertars.
>But i made -years ago- bad expirience with "propiety"
>backup formats not beeing readable by other software...

It's really not a proprietary format at all.  It's more 
like an enhanced tar. A couple of the main points are that
the supertars will backup empty directories and device node
entries while tar wont.

That means that if you have a directory that is sometimes full and
sometimes empty and you backup with a normal tar that directory
won't be backed up.

If this were a standard backup program that would be normal

But the supertars have the ability to boot from floppies, or CD
that you create to match your system, and if you lose a drive and
have a known good drive to put in, or if it's SCSI and
automatically heals itself, you can be restoring the complete tape
to a brand new hard drive in under five minutes.

If you used a tar/cpio backup you would have to reinstall the OS.
Then you would configure the tape device.  And only then would you
be able to reload the tape.

But SURPRISE.  Since the tar did not save empty directories those
aren't created and the first time a program that needs to use one
and can't find it, it might just blow up in your face.  So much for
most backup programs.  The supertar programs are 'backup systems'.

Same for device nodes.  I've seen MS people who can not believe it
when I have restored a complete system to a naked drive and had it
rebooted and running before they even got the MS bases OS
reinstalled.   Its then that you really appreciate these products.


>How "compatible" are those tapes (today)?

Quite.

>Currently one .com-company or software vendor or unix after 
>the next "dies".
>What if one bought a "supertape" software, changed system 
>and has to recover a tape made serveral years ago (had that in 
>a patent case) and can't get a running version of the supertar
>used then?

I"d have more faith in the ability to recover a tape made by a
supertar than I would on an MS system.  Because they are tar
compatible.

Worst case you could tar the files into a system and then massage
them by hand. And that would be very rare.

It was on an older version of one of these products and the data
was compressed before storage. [I won't name names because I've
only seen it a long time ago].

I need to extract data create on an SGI Challenge server [MIPS
based and the byte order is different than iNTEL chips].

The compressed were read via a NORMAL TAR command on a BSD system.
The files werent readable at first.  This problem - again a long
time ago - ws because the compressed files were restored but with 
no extension to indicate compression.

Running the 'file' command showed they were compressed.  I rename
of the files with an extension cured that.  [That was needed
otherwise the extracted file would want to overwrite the compressed
file in the same directory].

All ascii type files should restore perfectly.  I had some files
that were stored in the native CPU format on the SGI whose
byte-order is opposite of iNTEL.

So for those files I did this:

dd if=oldfilename of=newfilename conv=swab

And it was done.

So the only time you would find incompatibility - based on my
experience - is if you took a supertar file created on 
a different platform/cpu and move it to another with just
a little effort.

The supported platforms between the two major products include
SGI, Sun, HP-UX, Data General Avions, IBMs AIX, Dec Alphas,
NCRs towers, BSD, FreeBSD, Linux, and of course all SCO variants.

Let's see BackupExec match that !!!

They both support bootable CDs which will be used to restore the
tapes.  They both have network and dial in support.

You seem to indicate you have remote clients and both products
support dial-in modem and network support.

So you could have the remote client with a dead-system boot with
floppies or CD and then you could do the rest from your machine.

Truly amazing products.

I first started using these products back in 1986 when I did
on-call work for a site with 11 Xenix system and we had a supertar
backup on all of them with two port tape drives.  

In those days a 20MB drive then was considered large. And
those drives cost more than that time it was backup to multiple
floppies. Thankfully a 20MB drive then was considered large. And
those drive cost more than the 250GB drives you can buy todayn

Now those 1986 backup tapes would be hard to handle years later
- just as almost all old tapes will because there will be no
hardware to read them.. You'd have to look long an
hard to find a system with a Teac Cassette Data Drive to read
those tapes. But if you could the data would be readable today.

I think every major support person in this NG insists their
customers use one or the other.

Once you use them you'll wish you had them for the MS systems.

Bill

-- 
Bill Vermillion - bv @ wjv . com
 

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