Veritas-bu

[Veritas-bu] To ensure overwrites

2000-11-14 11:20:25
Subject: [Veritas-bu] To ensure overwrites
From: Bob Bakh bbakh AT veritas DOT com
Date: Tue, 14 Nov 2000 08:20:25 -0800
Unless the FBI and the NSA have better technology than the Private sector,
like all that alien stuff they have in Roswell.  There is no way to retrieve
data off a DLT 7000 tape that has been partly written over, I know I've
tried.

AIT I think is in the same boat, no one has cracked the compression on it.

As far as I know.  That is why in the first generation of DLT 7000 you had
enough trouble reading a tape drive to drive.  AIT has been a little more
reliable in that case, but I don't think getting passed a EOF mark will give
you the keys to the kingdom.

Bob

-----Original Message-----
From: KevinB AT paccessglobal DOT com [mailto:KevinB AT paccessglobal DOT com]
Sent: Friday, November 10, 2000 1:14 PM
To: John_Wang AT enron DOT net; KevinB AT paccessglobal DOT com
Cc: curtis AT colltech DOT com; veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] To ensure overwrites


I have not used the mt erase command but the assumption would be that it
would be more efficient.  This is assuming that, like most of the mt
commands, that mt is giving the tape drive the erase command.  The drive
then performs the work.  At a minimum this would eliminate the server work
and network traffic associated with a dd solution.  You also would not have
to worry about streaming your bit pattern fast enough to keep the drive
max.ed.  The Quantum manual for a 7000 DLT says the erase command can take
well over an hour (this implies less than 2 hours). 

-----Original Message-----
From: John_Wang AT enron DOT net [mailto:John_Wang AT enron DOT net]
Sent: Friday, November 10, 2000 12:54 PM
To: KevinB AT paccessglobal DOT com
Cc: curtis AT colltech DOT com; veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] To ensure overwrites




Hello

OK, so we all agree, a bplabel still leaves the data accessible to whomever
can
forward over an eom mark.   dd'ing a pattern is relatively straightforward
but
can take some time depending on how much needs to be overwritten.   What
about
"mt erase", any comments?

Regards,
John I Wang
Sr. Systems Engineer
Steverson Information Professionals

---
Enron Broadband Services
Enron Building 1472c
ph (713) 345-4291
fax (713) 646-8063


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I believe you would also want write a script that dd'ed a bit pattern over
the tape.  The question is, which is going to be slower, the dd process or
the degauss/relabel process.  From an automation perspective I think the
relabel overwrite method would be easier to implement.  If the risk of data
theft from backup tapes is that critical then perhaps the cost of several
new drives for this would be justified.

-----Original Message-----
From: W. Curtis Preston [mailto:curtis AT colltech DOT com]
Sent: Wednesday, November 08, 2000 4:49 PM
To: John_Wang AT enron DOT net; veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] To ensure overwrites


I would:
1. Create a pool just for those backups
2. Force those backups to that pool (class definition)
3. Relabel tapes older than a week.  (Relabeling them renders them
unusable.)

You DON'T want to degauss tapes if you plan on reusing them, depending on
the drive.  A degaussed tape returned to a DLT drive will take about 2
hours to get ready for use.  (It has to rewrite the headers on boths ends
of the tape.)

At 03:13 PM 11/8/00 -0600, John_Wang AT enron DOT net wrote:


>Hello Everyone
>
>We have a political requirement to ensure that certain backup images do not
>exist after a weeks time.   Any way to ensure that a tape gets overwritten
as
>soon as possible?   Can I prevent multiple images from being stored on
>tapes in
>a specific pool? i.e.: prevent multiple expiry dates on a given
>tape.   Short of
>removing expired tapes for degaussing, which will be done if that's the
>solution, what can be done to meet this requirement?
>
>Comments, ideas?
>
>Regards,
>John I Wang
>Sr. Systems Engineer
>Steverson Information Professionals
>
>---
>Enron Broadband Services
>Enron Building 1472c
>ph (713) 345-4291
>fax (713) 646-8063
>
>
>_______________________________________________
>Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
>http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu

---
W. Curtis Preston, Principal Consultant at Collective Technologies
Email: curtis AT colltech DOT com                (Best way to contact me)
Work : 408 452 5555                       (Leave a message.)
Pager: 800 946 4646, pin#1436065        (If urgent.)

Tap into the Collective Intellect (TM): http://www.colltech.com
Backup & Restore resources:        http://www.backupcentral.com

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